Credit card pay
We had to cancel our credit card do to fraud. Now apple will not allow us to delete the old card and add new card. States that we have to use old card for renewal. It is now canceled. Help
iPad Air, iOS 12
Try adding the new card and removing the old one via https://appleid.apple.com/account/manage
If that also doesn't work contact iTunes Support and see if they can help you do it : http://www.apple.com/support/itunes/ww (click on your country's flag, the country where you live, and which is therefore the country on the account ; click on Contact Support towards the top right ; click on Get Help under 'Talk To Us’)