Considering that VISA/Mastercard Operating Rules both consider an email to be acceptable written notification for submitting a chargeback, I think you'd have a hard time convincing auditors and examiners that this isn't written notification.
That being said, the commentary to Reg E 1005.11 gives you an out, but that out must be in your disclosures to apply. This also means that whomever reads these emails must be trained to provide an appropriate response to the customer.
Notice at particular phone number or address. A financial institution may require the consumer to give notice only at the telephone number or address disclosed by the institution, provided the institution maintains reasonable procedures to refer the consumer to the specified telephone number or address if the consumer attempts to give notice to the institution in a different manner.
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