Apple Pay credit card account closure issue

Are you confusing Apple Pay and Apple Account? Apple Account is where card details are stored and used for purchasing apps, music, videos and other Apple products and services.

Apple Pay is a technology that makes Tap-To-Pay more secure and private. Apple Pay is not an account.

What is the exact wording of the message? What were the steps you took leading up to this message?

We cannot tell, for example, if “my account” means the credit card you just entered, or perhaps some other account related to your Apple interactions.