It's not only Bangkok Bank,KBank does the same thing. Is your phone number registered in your name? Thats what this is about. You might have to visit your sim-card provider and get a receipt showing your phone number and your name. Then go to your bank branch.Bring bank book and passport and update the info.It must be done in person.
I really enjoy reading feisty comments between tourists about how to withdraw money the cheapest way in Thailand. That's why I love my KBank (or Bangkok Bank) card. No fees whatsoever. 👍
The O-A was also for many years known as a retirement visa at several embassies in Europe. The 50 year of age requirement has nothing to do with the official retirement age in western countries.