Declined card : If your payment method is declined, or you have a billing issue with a previous purchase in the iTunes Store - Apple Support
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). Credit cards seem more likely to work than debit cards.