Answer from John: Your customer is required to deal with your bank in order to press her claim. Although you get extra time to complete your investigation, you do have to decide whether you have evidence that the alleged error occurred, and complete the error resolution process accordingly. You have two conflicting versions of what happened to weigh. If you decide for the customer, you owe her $100 (and any fee resulting from the overcharge), in which case it appears your bank will be "out" the $100. If you believe the ATM owner is more credible, you can deny the claim.
Answer from Andy: Because your transaction was overseas you can use the exception under Section 1005.11(c)(3)(ii) and take up to 90 days to complete your investigation. If you take more than the standard 10 business days however, you will have to pay provisional credit.
First published on BankersOnline.com 1/28/13