Whether or not your bank can return the transactions is essentially irrelevant, but if the transactions are, in fact, unauthorized, you could go after the ODFI based on its warranty under the ACH rules that proper authorizations were obtained by the Originator. But I digress.
A strict read of Section 205.6 cuts off the bank's liability to the consumer for the series of unauthorized ACH entries at the 60th day following the delivery of the statement that reflected the first unauthorized EFT (UEFT) in the series. So suppose that the cell phone carrier's charges hit the customer's account every month on the 15th and the statements are cut on the last calendar day of every month, for delivery within two business days. Let's suppose also that the first alleged UEFT hit the account on 1/15/2010 and the last hit on 10/15/2010, and that the customer contacted the bank on or about 3/15/2011.
Under those assumptions, and a further assumption that the bank can't reasonably determine that the alleged UEFTs were authorized, the bank would be liable to the customer for the UEFTs that hit the account on or before 4/3/2010 (the 60th day after 2/2/10, which is the delivery date of the statement reflecting the first in the series of UEFTs). That means the bank would reimburse the customer for the 1/15/10, 2/15/10, and 3/15/10 UEFTs.
The fairest way to determine the bank's obligation to reimburse for fees and unpaid interest would be to recast all the customer's statements and balances starting from 1/15/10 as if none of the three reimbursed UEFTs had posted. Each overdraft fee that would not have been charged would be rebated, and interest for each month recalculated. Taking this to the extreme, each rebated fee and each interest credit would be value-dated so that future balances for each intervening statement would be recast, too.
I don't think that the regulation takes matters to that extreme, though. Candidly, I'm not sure that most banks would have the systems available to complete such an analysis. If a customer started pushing to have such a thorough analysis completed, I think I'd suggest offering to settled on a reasonable compromise rather than drive yourself crazy.
John S. Burnett
Fighting for Compliance since 1976
Bankers' Threads User #8