I canot add my debit card to wallet app

See the following Apple articles:

Set up Apple Pay -> Set up Apple Pay - Apple Support

Countries and regions that support Apple Pay

Countries and regions that support Apple Pay - Apple Support (EG)

If you can't add a card to Apple Wallet to use with Apple Pay

If you can't add a card to Apple Wallet to use with Apple Pay - Apple Support

• Apple does not approve or decline cards for use with Apple Pay. If your card was declined, contact your bank or card issuer.

I had the same problem too, but I read somewhere it did not have anything to do with the one under payments etc but until I went into general and into Language and Region to change it from there. That worked for me. I changed it and it worked.