How do I delete old debit cards

Hi

To remove a card from Apple Pay and add a new one:

Follow the instructions here:

• Manage the cards that you use with Apple Pay - Apple Support
• Set up Apple Pay - Apple Support
• Get help adding cards to Apple Pay - Apple Support

To change your Apple ID (including iTunes Store) payment method:

Follow the instructions here including checking that your address details fully match those on file with your card issuer / bank:

Change or remove your Apple ID payment information - Apple Support

The payment method that you are trying to use may not be a supported payment method.

Payment methods you can use in the iTunes Store, App Store, and iBooks Store - Apple Support

If you still need help, then contact iTunes Support:

Contact - Official Apple Support

(I'm afraid that no-one here can assist you directly. This is a user-based technical support community - you are not talking to Apple here).