Answer:
The customer has satisfied their requirement under Reg E to notify the institution of an error. The inability to file a chargeback with VISA does not relieve the institution of its obligation to investigate or provide provisional credit. You cannot deny a claim simply because a customer does not provide additional documentation. Since you are unable to file a chargeback, your options are reduced to honoring the claim or contacting the merchant directly in an attempt to obtain documentation to aid in your investigation.
First published on BankersOnline.com 9/17/12.