Amex chargebacks in the UK: deadlines, R13 and R03, and how to respond

Most chargeback advice is written for Visa and Mastercard. Then an American Express dispute lands with its own clock, its own labels and a short list of ways to lose without being wrong. Miss one and the reason code says you never replied.

Amex chargebacks run on a shorter, stricter timetable than many merchants expect, with a 20-day response window in the merchant guide summaries we reviewed. This guide explains how Amex chargebacks work for UK Shopify stores, what the R13 and R03 codes mean in plain words, what to send and how to avoid the two classic losses, no reply and an insufficient reply, with templates, worked sums and a day-by-day plan.

Last updated: 9 October 2026. Written by the ChargeFix team.

The 30-second answer (TL;DR)

• Amex chargebacks come with a 20-day window to respond to an inquiry or a chargeback, according to the Amex merchant guide material we reviewed. Always follow the due date on your own notice, because Shopify shows its own 7 to 21 day window for disputes it handles.
• Two reason codes catch merchants out. R13 means no reply was received. R03 means the reply was insufficient. Both are losses caused by process, not by the facts of the order.
• Older Amex rules were reported in an ombudsman decision as having a 45-day limit. We did not verify whether that still applies, so treat 20 days as the planning figure and respond early.
• Win by answering the stated reason with specific, labelled evidence: delivery proof for item not received, listing and photos for not as described, refund records for credit disputes.
• Credit card buyers may also have Section 75 rights for purchases between £100 and £30,000, with a six-year limit, according to UK Finance. That runs separately from a chargeback.
• Winning does not remove a dispute from your chargeback rate, according to Shopify's help centre.
• General information, not legal advice. We did not review how every Amex dispute appears in the Shopify admin, or the full Amex reason code list, and the post says so where it matters.

From dispute to decision

Stage	What happens	What you do	What you need as proof
Inquiry	Amex asks for information about a charge	Reply fully inside the window	A complete first response
Chargeback raised	Amex debits or holds the amount, subject to its rules	Log it and set the due date	The notice and its reason
Response window	20 days in the merchant guide summaries we reviewed	Submit early, complete and labelled	Evidence pack, strongest first
No reply	Recorded as R13	Avoid by never missing the date	A submission confirmation
Insufficient reply	Recorded as R03	Avoid by answering the stated reason	Evidence that fits the reason
Decision	Amex decides under its rules	Record outcome and fee	Log row and cash effect

What are Amex chargebacks and how does American Express handle them?

Amex chargebacks are disputes raised by an American Express cardholder, or by Amex on their behalf, over a charge on their card. The cardholder asks Amex for the money back, Amex notifies you and you respond with evidence. Amex then decides under its own merchant rules.

American Express runs its own card network, so its dispute process has its own wording and its own timetable. That is why advice written for Visa and Mastercard does not always map across. The principles are the same: answer the stated reason, send specific evidence, respond on time. The details differ.

For the general card process on Shopify, read our Shopify chargebacks UK guide. Shopify's help centre explains that Shopify is not liable for chargebacks and that you respond with evidence. That holds for Amex chargebacks handled through Shopify Payments.

Two limits on what we can say. First, we did not review how Amex disputes appear in the Shopify admin for every account setup. If you take Amex through Shopify Payments, check a recent Amex order on your own store. If you take it through a separate merchant arrangement, your disputes may reach you through that route instead. Second, we did not review the complete Amex reason code list. We know two codes from the material we reviewed, and we explain them below.

If you take several payment methods, the deadlines differ. See PayPal dispute vs chargeback, Klarna disputes on Shopify UK and Clearpay disputes for merchants.

How long do you have to respond to Amex chargebacks?

The Amex merchant guide material we reviewed gives 20 days to respond to an inquiry or a chargeback. An ombudsman decision referred to an older 45-day limit under previous rules. We did not verify which applies to your account today, so plan on 20 days or the date on your notice, whichever is earlier.

Shopify's help centre gives a response window of 7 to 21 days for disputes handled through Shopify, so the date on the dispute in your admin is the one to follow. If the dates disagree, use the earliest. Never plan on the longest figure.

An example makes the arithmetic concrete. Suppose a notice arrives on Monday 5 October 2026 with a 20-day window.

Date	Day	Event
Monday 5 October 2026	Day 0	Notice arrives
Wednesday 7 October 2026	Day 2	Decision made: fight, refund or accept
Wednesday 14 October 2026	Day 9	Evidence pack drafted
Friday 16 October 2026	Day 11	Second person reviews
Wednesday 21 October 2026	Day 16	Planned submission
Friday 23 October 2026	Day 18	Latest sensible submission
Sunday 25 October 2026	Day 20	Window ends

The window ends on a Sunday in this example. We did not verify how weekends and bank holidays are treated, and we did not verify the time of day or time zone of the due date. So treat Friday 23 October as your real deadline. Check the weekdays against a calendar: 5 October 2026 is a Monday, 7 October a Wednesday, 14 October a Wednesday, 16 October a Friday, 21 October a Wednesday, 23 October a Friday and 25 October a Sunday.

Put the due date in a shared calendar the day the notice arrives, with reminders at day 10 and day 15. Our chargeback SOP for small teams gives the routine.

What do R13 and R03 mean on Amex chargebacks?

R13 is the code for no reply. R03 is the code for an insufficient reply. They are the two ways to lose an Amex chargeback through process: not answering at all, or answering with something that does not address the reason. Both are avoidable.

The sources we reviewed give these two codes. We did not review the full code list, so do not read this section as a catalogue.

Code	Plain meaning	How merchants trigger it	How to avoid it
R13	No reply received in time	Missed due date, notice in the wrong inbox, no named owner	Shared calendar, named owner, backup person
R03	Reply received but insufficient	Evidence that does not answer the stated reason, missing items, unlabelled files	Match proof to the reason, label exhibits, send a complete pack

Think of R13 and R03 as the "paperwork" losses in Amex chargebacks. They do not say the buyer was right. They say the file was not there or not enough. Both are in your control.

Here is how R03 happens in practice:

1. The reason is item not received. You send a screenshot of the order and nothing about delivery.
2. The reason is not as described. You send tracking, which proves delivery and says nothing about the item.
3. The reason is credit not processed. You send a policy page but no refund record.
4. The pack is correct but the files are unlabelled and out of order, so the reviewer cannot find the key item.

The fix for Amex chargebacks is a short mapping from reason to proof. Use the table below as a starting point, and adapt it to the wording on your notice.

Stated reason	The question the reviewer asks	Lead with
Item not received	Did the goods reach the cardholder?	Carrier proof of delivery, address match
Not as described	Did the goods match what was sold?	Listing capture, photos, packing notes
Credit not processed	Did the merchant refund as promised?	Refund record with date and reference
Cancelled or recurring	Did the merchant honour the cancellation?	Terms, cancellation request and date
Unauthorised	Did the cardholder make or authorise the charge?	Order record, delivery to the cardholder's address, history
Duplicate	Was the cardholder charged twice for the same thing?	Both order records and what each covered

How do you answer Amex chargebacks so the reply is not insufficient?

To answer Amex chargebacks well, answer the stated reason, in the first lines, with the strongest proof first and each exhibit labelled. A reviewer should be able to read the summary, see the key exhibit and decide in under two minutes. Anything that does not answer the reason can wait at the end or be left out.

Start with a short factual summary. Use this template and adapt it to the reason:

Order [ORDER NUMBER], £[AMOUNT], placed [DATE] by [BUYER NAME], paid by American Express ending [LAST FOUR].

Reason on the notice: [REASON AS STATED].

Summary: [ONE TO THREE SENTENCES THAT ANSWER THE REASON DIRECTLY. FOR ITEM NOT RECEIVED: The order was dispatched on DATE with CARRIER, tracking NUMBER. The carrier recorded delivery to ADDRESS on DATE at TIME, with signature of NAME / photo of the parcel at the address.]

Exhibits, strongest first:
1. [KEY EXHIBIT FOR THE REASON], dated [DATE]
2. Order record showing the address and payment method
3. Order confirmation email, sent [DATE] at [TIME]
4. Tracking history or refund record
5. Our messages with the cardholder, [DATE] to [DATE]
6. Our delivery and returns policy, published [DATE]

We ask the reviewer to consider the exhibits above and decide in our favour.

Shopify's help centre says responses are made on the order's chargeback response form, that screenshots are preferred to external links, and that you should label each piece and put the strongest first. After the due date nothing can be added and the result is final. We did not verify whether a submitted response can be edited, or file type and size limits. Check the form when you respond, and treat submission as one shot.

Add these habits:

1. Put the answer to the reason in the first paragraph.
2. Number the exhibits and refer to them by number.
3. Keep each exhibit to one page or one screenshot where you can.
4. Quote dates and times exactly.
5. Do not accuse the cardholder. Describe the facts.
6. Re-read the notice before you submit, and check each exhibit against the reason.

Use this checklist before you submit:

• The summary answers the stated reason in the first lines
• The strongest exhibit is first
• Every exhibit is legible, labelled and dated
• No exhibit contradicts another
• Refund records are included wherever a refund is mentioned
• The response was submitted at least two days before the due date
• A screenshot of the submission confirmation is saved
• The log row records the submission date

What evidence works for item not received on Amex chargebacks?

Carrier proof of delivery, matched to the order address, is the core. Add tracking, the confirmation email and messages. A signature or photo beats a bare delivered scan. Keep the strongest proof at the top and the rest in a clean order.

Item not received is the most common reason behind Amex chargebacks for small UK stores, and the evidence ladder is the same across card types.

Evidence	Strength	Why
Signature from the recipient	Strong	A named person accepted the parcel
Delivery photo with a time stamp	Strong	Shows where the parcel was left
Tracking with a final delivered scan	Medium	Proves the carrier's claim, not who received it
Proof of postage only	Weak	Shows you sent something
Messages from the buyer confirming receipt	Strong	Their own words contradict the claim

Royal Mail captures a photo on delivery for Tracked 24 and Tracked 48 where no signature is needed. Evri offers a Digital Signature add-on with photographic proof, at 60p when we checked, and the price may change. We have not verified DPD's proof options. Our guide to proof of delivery for Shopify chargebacks explains the differences. For orders sent in several parcels, build a parcel ledger as shown in split and partial shipment disputes.

Some Amex cardholders buy with corporate cards, so delivery to a work address or a reception desk can be common for your store. If that is your situation, make sure the delivery instructions and the proof say who signed. An unnamed signature at a reception desk is weaker than a named one.

Should you fight Amex chargebacks or accept them? Two worked examples

With Amex chargebacks, fight when you hold strong proof and the order is worth the effort. Accept or refund when the proof is thin, the order is small or the complaint is fair. A complete pack costs time, so run the sums before you decide.

Both examples are illustrations with invented numbers. The arithmetic is checked. We did not verify the fee for Amex disputes on Shopify, so we assume Shopify's UK fee for card chargebacks of £10, charged by the bank and returned if you win.

Example 1: fight, lose or accept one of the Amex chargebacks. An Amex cardholder disputes a £240.00 order as not received. The goods cost £96.00. You hold a signed delivery and the confirmation email.

Case	Revenue kept	Goods cost	Fee	Net result
Fight and win	£240.00	£96.00	£0.00	£240.00 − £96.00 = £144.00
Fight and lose	£0.00	£96.00	£10.00	£0.00 − £96.00 − £10.00 = minus £106.00
Accept	£0.00	£96.00	£10.00	Minus £106.00

The swing between winning and losing is £250.00. Accepting costs the same as losing, so fighting is never worse in cash terms. The real cost of fighting is your time. With a signature and a clean pack, it is usually worth it.

Example 2: is a complete pack worth the extra time? A store has a £300.00 Amex dispute. A basic reply takes 30 minutes and has a 30% chance of winning. A complete pack takes 75 minutes, which is 45 minutes more, and has a 45% chance. Time is valued at £25.00 an hour. These win chances are invented for the example.

Item	Calculation	Amount
Extra time	45 minutes = 0.75 hours × £25.00	£18.75
Extra chance of winning	45% − 30%	15 percentage points
Value of a win	£300.00 + £10.00	£310.00
Expected extra gain	0.15 × £310.00	£46.50
Net benefit of the complete pack	£46.50 − £18.75	£27.75

On these numbers the complete pack adds £27.75 of expected value, because an insufficient reply is the avoidable way to lose. If the order is £30.00, the same extra chance is worth 0.15 × £40.00 = £6.00, which is less than the £18.75 of time, so a short reply or a refund is sensible. Nothing here predicts an outcome.

Situation	Suggested move	Reason
Signature or photo, address matches	Fight	Strong, specific proof
Delivered scan only, order over £100	Fight, add confirmation and messages	Medium proof, enough at stake
No delivery event	Refund or reship	You cannot prove arrival
Credit not processed, refund issued	Fight with the refund record	Facts are on your side
Small order, thin proof	Refund early	Your time costs more

Day-by-day plan: respond to Amex chargebacks inside the 20-day window

Treat the day the notice arrives as day zero and the due date as your fixed point. The plan below uses the 20-day window. Read the date on your own notice, and move every step earlier if it is shorter.

Day	Task	Output
Day 0	Log it. Set the due date and reminders at day 10 and day 15. Open the order	Log row and reminders
Day 1	Note the reason, amount and payment method. Check for refunds already issued	One-line triage
Day 2	Decide: fight, refund or accept. Write the decision and the date	A dated decision
Days 3 to 5	Pull proof for the stated reason, strongest first	Evidence folder
Days 6 to 8	Chase gaps with the carrier or the buyer. Reship or refund if proof is missing	Updated folder
Day 9	Write the summary and label exhibits	Draft response
Day 11	Second person checks the pack against the reason	Comments
Day 14	Fix any gaps	Final pack
Day 16	Submit and screenshot the confirmation	Submission recorded
Day 18	Latest sensible submission date	Fixed
Day 20	Window ends	None
Decision day	Record outcome, fee and cash effect	Closed row

If the notice shows a shorter window, compress the same steps. A 7-day window means: decide on day 1, gather on day 2, review on day 3, submit on day 4.

What if the cardholder is also a Section 75 claimant?

A cardholder who paid by Amex credit card may have two routes: a chargeback under card scheme rules and a Section 75 claim against the card company. They are separate. Section 75 covers purchases between £100 and £30,000 and lets the buyer claim against the card company as well as the merchant.

UK Finance says the Section 75 time limit is six years, much longer than the usual 120 days for chargeback. MoneyHelper describes Section 75 as applying to credit cards only, with the card company jointly liable.

What this means for you:

1. Keep order, delivery and refund records longer than the chargeback window.
2. A won chargeback does not rule out a later Section 75 claim. We did not review how card companies handle that in practice.
3. If you receive a request for information from a card company about a Section 75 claim, respond just as you would to a dispute notice, and ask your adviser how to handle it.

We did not review whether Amex charge cards, which are not credit cards in the Section 75 sense, behave differently. If you serve many corporate or charge card holders, ask your adviser how this applies.

How do you prevent Amex chargebacks?

To prevent Amex chargebacks, make the purchase easy to recognise, easy to follow and easy to fix. A clear statement descriptor, an order confirmation, tracking, signature on higher-value orders and fast replies prevent most disputes. Add a shared calendar and a named backup so you never trigger R13.

Use this checklist:

• Statement descriptor matches your trading name
• Order confirmation names your store, lists items and gives the total
• Tracking emails go out for every parcel
• Higher-value orders ship with a signature or photo
• Delivery and returns pages are live, dated and linked in the footer
• Disputes arrive at an inbox watched by two people
• A named backup knows the process and has access
• Every dispute is logged, including wins

Shopify Payments has a statement descriptor setting. We did not verify the current menu wording, so check your payment settings. Our shipping and delivery policy template and terms and conditions template give you wording for the pages a reviewer will read.

If you take large Amex orders from business buyers, add a line to your terms about purchase orders, delivery to reception and who can sign. Business buyers often have internal rules on card spend, and a clear paper trail helps when a finance team asks questions.

What does a weak and a strong reply to Amex chargebacks look like?

A weak reply states a conclusion and attaches everything. A strong reply states the facts that answer the reason and attaches only what supports them. The difference is often what separates a paperwork loss from a fair hearing on the facts of the order.

Take an item not received dispute. Here is a weak summary, followed by a strong one built from the same facts.

Weak:

The customer received the item. See attached. Please reject the chargeback.

Strong:

Order #1187, £240.00, placed 2 October 2026, paid by American Express.

Reason: item not received.

The order was dispatched on 3 October 2026 with Royal Mail Tracked 48, tracking [NUMBER]. The carrier recorded delivery to the address on the order on 6 October 2026 at 11:42, with a photograph of the parcel at the front door (exhibit 1). The delivery address is the one the cardholder supplied at checkout (exhibit 2). We emailed tracking on 3 October (exhibit 3) and the cardholder did not contact us about delivery before the dispute.

The strong version does four things. It names the reason. It gives dates and times. It points to numbered exhibits. It avoids opinions. A reviewer can check each claim in seconds.

Use the same method for each reason: write the one-paragraph answer first, then make sure every sentence has an exhibit behind it. If a sentence has no exhibit, either find one or cut the sentence. Avoiding R03 is mostly this discipline.

How do business and corporate cardholders affect Amex chargebacks?

Orders paid on corporate cards often involve a finance team, a purchase approval and a delivery to an office. Disputes can arise from internal reconciliation rather than dissatisfaction. A clear invoice, a named contact and a delivery signature reduce the chance of a surprise.

We did not review data on how common corporate cards are among Amex cardholders who buy from Shopify stores, so treat the following as general practice for merchants who sell to businesses.

1. Send a proper invoice or order confirmation with your legal name, address and any VAT number you hold.
2. Record who placed the order, who approved it and who received it, where you can.
3. Ask for a named recipient and a phone number for delivery to an office.
4. Use a signature service for higher-value parcels to workplaces.
5. If a finance team asks about a charge, answer within a working day with the order record and the delivery proof.

A quick reply to a finance query can settle a question before it becomes one of the Amex chargebacks you have to answer formally. Keep a template ready:

Hi [FINANCE CONTACT],

Thanks for your query about the charge of £[AMOUNT] on [DATE].

It is for order [ORDER NUMBER], placed by [BUYER NAME] on [DATE], covering [ITEMS]. It was delivered to [ADDRESS] on [DATE] and signed for by [NAME]. I have attached the invoice and the delivery proof.

If you need anything else for your records, reply and I will send it today.

[YOUR NAME]
[STORE NAME]

Quick rules for Amex chargebacks

Keep these where your team can see them. They sum up how to handle Amex chargebacks calmly and consistently.

1. Put the due date in a shared calendar the day the notice arrives, and submit at least two days early.
2. Never trigger R13. Name an owner and a backup, and watch the inbox that receives notices.
3. Never trigger R03. Answer the stated reason, in the first lines, with the strongest proof first.
4. Do not assume Visa and Mastercard timings apply to Amex chargebacks.
5. Keep records for longer than the chargeback window, because Section 75 claims on credit cards can run for six years.
6. Log every dispute, including wins, because winning does not remove it from the chargeback rate.

What's different for UK merchants

This section is general information, not legal advice.

• Amex chargebacks deadlines: the merchant guide material we reviewed gives 20 days to respond to an inquiry or chargeback. An ombudsman decision referred to an older 45-day limit. Follow the date on your own notice.
• Reason codes: R13 means no reply and R03 means insufficient reply, per the sources we reviewed. We did not review the full list.
• Shopify: Shopify's help centre says Shopify is not liable for chargebacks, gives a 7 to 21 day response window and says winning does not remove a dispute from the chargeback rate.
• Fees: Shopify's UK fee for card chargebacks is £10, charged by your bank and returned if you win. We did not verify the fee for Amex disputes.
• Time limits: MoneyHelper describes chargeback as a voluntary card-scheme arrangement, usually claimed within 120 days. UK Finance gives the same period, counted from the transaction or the expected delivery.
• Section 75: for credit card purchases between £100 and £30,000, the card company is jointly liable with the merchant. UK Finance says the time limit is six years.
• Consumer rights: the Consumer Contracts Regulations 2013 give most distance buyers a 14-day cancellation right, with a refund due within 14 days of getting the goods back or evidence of return.
• Shopify Protect: it does not cover UK stores, so your evidence is your own protection.
• Weekends and bank holidays: we did not verify how they affect due dates. Respond early.

Common mistakes

1. Planning for Amex chargebacks on the longest window instead of the date on the notice.
2. Letting a dispute notice sit in an inbox nobody checks, and triggering R13.
3. Sending evidence that does not answer the stated reason, and triggering R03.
4. Sending an unlabelled folder of files with the key exhibit buried.
5. Assuming Visa and Mastercard timings apply to Amex chargebacks.
6. Accusing the cardholder instead of presenting dated facts.
7. Forgetting that a Section 75 claim can arrive years later on a credit card payment.
8. Skipping wins in the log of Amex chargebacks, then miscounting the chargeback rate.

FAQ

How long do I have to respond to Amex chargebacks?

The Amex merchant guide material we reviewed gives 20 days to respond to an inquiry or chargeback. An ombudsman decision referred to an older 45-day limit. Follow the due date on your own notice, and submit at least two days early. We did not verify weekend or time zone treatment.

What does R13 mean on an Amex chargeback?

R13 is the code for no reply received, according to the sources we reviewed. It means the merchant did not respond in time. It is a process loss, not a finding that the cardholder was right. A shared calendar and a named backup person prevent it.

What does R03 mean on an Amex chargeback?

R03 is the code for an insufficient reply. The merchant responded, but the evidence did not answer the stated reason or was incomplete. Prevent it by matching proof to the reason, labelling each exhibit, putting the strongest proof first and re-reading the notice before you submit.

Are Amex chargebacks harder to win than Visa chargebacks?

We found no reliable source with comparative win rates, so we cannot say. Amex has its own rules and timetable. The practical difference is the short window and the need to answer the exact reason. Judge your results from your own dispute log.

Does Shopify handle Amex chargebacks?

If you take Amex through Shopify Payments, disputes follow the Shopify process, with its response form and window. We did not verify how every account setup presents Amex disputes. Check a recent Amex order on your store, and ask Shopify support if your setup differs.

Does Section 75 apply to Amex payments?

Section 75 covers credit card purchases between £100 and £30,000, with the card company jointly liable, according to MoneyHelper and UK Finance. Whether it applies to a given Amex card depends on the card type. We did not review Amex charge cards, so ask an adviser if you serve many.

Can I fight Amex chargebacks after the deadline?

Assume not. Shopify's help centre says nothing can be added after the due date and the result is final, and Amex treats a missed reply as R13. Put the due date in a shared calendar the day the notice arrives, with reminders, and submit early.

What evidence should I send for Amex chargebacks on item not received?

Carrier proof of delivery first, ideally a signature or photo, then tracking, the order record showing the address, the confirmation email and any messages. Label each exhibit and put the strongest proof first. Answer the stated reason in the opening lines of your summary.

Should I refund an American Express cardholder who raises Amex chargebacks?

Sometimes. If the order is small, the proof is thin or the complaint is fair, an early refund is often cheaper than a lost dispute. Ask your payment provider how a refund interacts with an open dispute, because that is not covered in the sources we reviewed.

Do Amex chargebacks count against my chargeback rate if I win?

Shopify's help centre states that winning does not remove a dispute from the chargeback rate. Log every dispute, including the ones you win. Prevention matters as well as response, so review your reasons and fix the biggest cause each month.

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Sources

• Shopify Help Center: Chargebacks and inquiries
• UK Finance: Chargeback and Section 75
• legislation.gov.uk: Consumer Contracts (Information, Cancellation and Additional Charges) Regulations 2013, explanatory note
• Stripe, Best practices for preventing fraud: further reading on stopping disputes before they start
• Adyen, Manage disputes: further reading on how another payment provider handles disputes