Understanding American Express Chargeback Reason Code P22: Non-Matching Card Number

American Express issues Reason Code P22 when a transaction is processed with a card number that does not match the one used for the initial authorisation. This code signifies a processing error has occurred. The most frequent causes behind this chargeback are simple human error, particularly when manually keying in transaction details, or a technical malfunction with a payment terminal.

Key Takeaways

• What it means: The card number used in settlement did not match the number authorised for the transaction.
• Causes: Manual keying errors, terminal read faults, software mapping issues, or wrong stored credentials.
• How to respond: Act fast, compare authorisation and settlement data, and submit clear evidence within the time limit.
• How to prevent: Use chip/contactless reads. Follow strict processing steps. Avoid manual entry. Reconcile daily.

What is an American Express Reason Code P22 Chargeback?

Reason Code P22, “Non-Matching Card Number,” is an American Express chargeback raised when the card number included in the merchant’s charge submission differs from the card number that received the original authorisation. In practical terms, the transaction may have been approved against one account, but the settlement sent to the acquirer references another account number. This is a processing error, not a claim about product quality or fraud.

What is a P22 chargeback telling you? It is a signal that something went wrong between authorisation and settlement. This can occur in card-present and card-not-present environments. It might be a simple typing mistake during manual key entry. It might be a terminal that read a partial or corrupted card number. It could also stem from pulling the wrong stored credential file or a gateway mapping error that rewrites a PAN field.

In most cases, P22 is avoidable through tighter process control. It can, however, still happen if systems mishandle data or when staff bypass normal collection steps. While friendly fraud is rare in this category, it is not impossible. The best approach is to fix the process gap and keep clear, auditable records of each stage of the payment.

Primary Causes for a Code P22 Chargeback

Most P22 disputes start with small, preventable mistakes. The most common cause is manual key entry. A single missing or transposed digit can create a mismatch between the authorisation and the final charge. Even careful staff can make this error when rushing or reading from unclear notes.

Hardware and software faults can also trigger P22. A point-of-sale device may fail to read the chip or stripe correctly, passing an incomplete or altered number into the settlement file. Outdated terminals, damaged card readers, or loose connections can all contribute to this. In eCommerce, a gateway or shopping cart plugin might mis-map fields, especially after updates, causing the wrong value to sit in the PAN field at submission.

Stored credential use is another area of risk. If your team keeps more than one card on file for a customer, it is easy to select the wrong profile or token. Batch handling can add further complexity. Mixing items from multiple tills or resubmitting failed batches can introduce mismatched data. Skipping standard authorisation checks or reusing an old authorisation also raises the risk. Each of these causes leads to the same outcome: American Express sees a number mismatch and raises a P22 chargeback.

Time Limit for Disputing an American Express Reason Code P22 Chargeback

American Express sets a strict time limit for responding to P22. The acquirer or merchant has 20 days to submit their dispute response. This is a network-level deadline, and it includes the time your acquirer takes to forward the case to you and review your evidence before sending it back to American Express.

In practice, your working window may be short. You might have five days or fewer to collect documents, prepare your rebuttal, and return everything to the acquirer. If you miss the deadline, the chargeback stands by default. There is no extension for late submissions in the normal flow.

Plan for speed. As soon as you receive the notification, open a case file. Pull the authorisation response, terminal logs, and settlement records at once. If you need statements from staff, request them the same day. If a customer credit was already processed, obtain the credit memo and posting confirmation. Send your response well ahead of your acquirer’s internal cutoff. Meeting the time limit is as important as the quality of your evidence.

What P22 Means for Consumers & Issuers

For consumers, P22 is about accuracy. A cardholder might see a charge appear on a card they did not present, or a transaction linked to a number they do not recognise. This can be unsettling, yet the origin is often a merchant processing mistake, not card theft. Cardholders should review statements and report mismatches promptly. In many cases, the issuer will resolve the dispute without the consumer needing to do more than confirm the details.

For issuers, including American Express, P22 reflects a compliance and reconciliation function. The issuer compares the authorisation record with the settlement file. If the numbers do not match, the network process flags it, and a chargeback follows. Issuers will look for proof that the card number submitted at settlement matches the authorised number or for proof that a corrective credit has posted. P22 also informs risk controls. Frequent P22 cases from a merchant account may trigger monitoring, education, or even changes to processing permissions. For issuers, this means safeguarding data integrity and maintaining a fair and consistent ecosystem for all parties.

What P22 Means for Merchants

For merchants, P22 highlights gaps in payment handling. It often points to training needs, device maintenance issues, or weaknesses in stored credential management. Each case can carry fees, potential loss of the transaction value, and staff time spent gathering evidence. A pattern of processing errors can raise your chargeback ratio, which may lead to monitoring and higher costs.

Operationally, P22 can disrupt cash flow. If the transaction amount is significant, the write-off or delayed recovery matters. It also adds friction for customer service. Even when the root cause is internal, customers may blame the brand for appearing careless with their card details. This can hurt trust.

How to Respond to a Code P22 Chargeback

Start by verifying the claim. Pull the authorisation approval, including the full card number (masked as required), the date and time, and the approval code. Then pull the settlement or batch file submitted for that transaction. Compare the card number fields. If they match and the issuer data appears to be in error, you have grounds to fight the chargeback.

Prepare a clear rebuttal letter that explains what happened and what it means, step by step. Attach supporting documents. Helpful items include a terminal charge record showing the card was read electronically, a copy of the card imprint for manual transactions, POS or gateway logs showing the PAN at the point of sale, and the batch detail showing the same number at settlement. If you have already issued a refund, include the credit memo, date, and proof it posted.

Submit your package within the time limit. Stick to facts. Do not include unneeded personal data. If you find that the wrong card number was used at settlement, contact your acquirer about next steps, and credit the impacted account immediately to mitigate loss. You can then update your procedures to stop a repeat. When you know how to respond to or fight P22 with targeted evidence and fast action, your win rate improves.

Proactive Prevention: The Ultimate Defence

The most effective way to handle P22 chargebacks is to prevent them from happening. Always prioritise processing transactions electronically by using the card's chip or by swiping it. If manual entry is the only option, use a physical imprinter to create a carbon-copy record of the card's details as a reliable backup. 

Consider implementing a policy where a second staff member verifies any manually keyed card numbers before the transaction is submitted. It is also good practice to process your transaction batches at the close of each business day. Early warning tools can also help. Try out chargeback alerts to give you notice as soon as chargebacks arise, allowing you to refund or fix errors quickly.