I can’t remove my old card!

To find out how to remove a payment method, and what to do if you can't remove your last payment method or use no payment method with your Apple ID, read this article --> Remove a payment method from your Apple ID - Apple Support

Ongoing subscriptions and Family Sharing organizers must always have a payment method present. To edit the cards used for those you may need to first add the new card and make it the primary payment method before removing the old card (see: If you need to change or update your Apple ID payment method - Apple Support ).

I presume you meant credit card.

If you meant a SIM card, see: Remove or switch the SIM card in your iPhone - Apple Support

or take it to an Apple Genius Bar. Genius Bar Reservation and Apple Support Options - Apple

If you already tried (to no avail) to add the new card THEN delete the old one (as per this support article:--> If you need to change or update your Apple ID payment method ), I suggest that you contact iTunes Store Support Team directly, using this specific link:--> Apple Support .

(if you get no help, look at the bottom of the above link, where you can contact them using "chat" or "phone" options).

Regards

Giulio