by Jim Bedsole:
No. The only thing you gain in that scenario is that you don't have to provide provisional credit in order to take advantage of the longer investigation period (45/90 calendar days rather than 10/20 business days) if the customer doesn't provide written confirmation. But you still have to investigate and make a determination based on the investigation in response to the oral notice of alleged error.
by David Dickinson:
You can't take people's rights away from them. Reg E states customers can make oral claims of Reg E disputes. [§1005.6(b) and §1005.11(b)(1)]. You can ask customers to put disputes in writing, but you shouldn't tell customers that all Reg E disputes must be in writing.