Apple good advice overall. Thanks for your contribution.
Apple Support aren’t meant to be IT experts. The OP will receive an error message basically telling them to contact the bank for further assistance. The bank’s people are clueless and say it’s not our issue, call Apple. It’s the bank’s poorly trained support at the root of the issue.
The second thing is Apple servers/data bases play no role in providing account information. The information comes from the iPhone itself and is encrypted on the iPhone. When Apple receives the data it’s basically forward to the PNO (most banks use the PNO, but can use a third party). The PNO decrypts the data and verifies basic information the account holder submitted. For example any card errors such as wrong expiration date, invalid card number and it gets bounced back to Apple and then to iPhone with basic error message. Information on Apple servers never comes into play. If an address is wrong, it’s on the iPhone.