Reason code

American Express reason code S01 is used when a merchant requests a reversal or refund through Amex, but the request is denied—often because it falls outside Amex’s policies or timeframes. In these cases, Amex may process a chargeback instead to correct the situation and return funds to the cardholder.

This reason code usually reflects a situation where the merchant attempted to resolve the issue, but their request didn’t meet Amex’s technical or procedural requirements. Whether due to timing, missing documentation, or format errors, the result is a chargeback tied to the failed reversal.

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If your reversal request was valid, submit documentation proving it met Amex’s requirements:

• Include your original refund attempt, submission dates, and any Amex denial correspondence
  
  
• Provide system logs or evidence showing your actions complied with their guidelines

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Ensure your reversal requests meet Amex’s standards to avoid denials and chargebacks:

• Submit reversal requests promptly and in the correct format
  
  
• Double-check refund documentation and timing before relying on Amex processing

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