Card Declined for App Store

If necessary, contact iTunes Support. Either use the form or scroll to the bottom of the page in the 2nd link. Follow through the screens to get a chat or telephone option.

iTunes Support

iTunes Support – world wide

You use 'all the time' where ? Obviously being able to use the card elsewhere won't guarantee that it will pass the iTunes Store validation, nor if it used to work with iTunes is also no guarantee that it will continue to do so.

If it's a debit card that might be why it's being declined, not all seem to still be accepted by iTunes. Or the card issuer might be declining it for use with iTunes.

For a card to have a chance of being accepted it needs to be registered to the same name and address (including format and spacing etc) that you have on your iTunes account, and have been issued by a bank in the country where you are (and therefore the country which is on your iTunes account).

Validation rules can change over time, what is or isn't accepted by iTunes can change. Try removing the card and adding its details from scratch, or use a different card.