My Apple Pay and debit card have been disabled and I don’t know why

Same thing happened to me when I activated Apple Cash. You need to reenter your card’s CVV. In Settings, go to Wallet & Apple Pay. Click on the Apple Cash card and then the Add Money button; your other cards will show up and you can reauthorize a card by entering its CVV number. After the information is processed your card will be available again!

Can you post a screenshot of the warning? please edit out personal information.

go here - If you see a message that says 'Your account has been disabled in the App Store and iTunes'