Brian's ears were ringing.
1005.11(b) requires that the customer provide their name, account number and why they believe an error exists. Based on your description of the sequence of events, the customer is claiming that they revoked the authorization to charge the card when cancelling the wedding.
1005.11(a) defines an unauthorized or incorrect EFT as an error. We cannot deny a claim solely on the basis of the customer not providing enough evidence to give us chargeback rights. Reg E doesn't care whether we can use the chargeback process as a means of conducting our investigation.
It is entirely possible that the customer was charged a cancellation fee for which they do not want to be held responsible. If faced with this claim on my desk I would do two things. 1) Review the merchant's website to see if they have any default agreements posted on the site that I can use to demonstrate why the charge was authorized and not an error. 2) Call the merchant myself to see if I can find more information about the second charge if there is nothing on the website. Merchants want to avoid chargebacks as much as issuing banks do and they may be willing to provide some details about their side of the dispute.
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