We have a customer that informed us on 10/25/19 that they had informed American Express they were revoking their authorization to debit their account on 8/1/19. From my understanding this would now be considered an unauthorized transaction for Reg E and we are required to investigate. In order for it to be truly unauthorized however, and our investigation find in their favor, they would have to have not received benefit from the transaction. Is that accurate? Say it is found these transactions are payments to their credit card. Are they still unauthorized under the Reg E rules?

From 1005.2, the definition of unauthorized EFT:

(m) “Unauthorized electronic fund transfer” means an electronic fund transfer from a consumer's account initiated by a person other than the consumer without actual authority to initiate the transfer and from which the consumer receives no benefit....

If those transfers were made to the customer's Amex card account, you can deny the claim.

Thank you. I knew this, but started doubting myself.