I just need to update an expiration date and new 3 digit security code and am not able to do that. I can't remove the existing card or add a new card apparently because it cannot verify the old card. I've tried on iphone and on a pc but neither one will work.
iPhone 8 Plus, iOS 12
Try updating/removing it 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’)
Try updating/removing it 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’)
Do it on appleid.apple.com
Can't update credit card information
