How much you might owe (if anything) has no impact on whether a card is declined or accepted. If they are debit cards then that might be why they aren't accepted, not all seem to still be - and prepaid cards are also likely not to work.
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). If your cards are then you've checked with the card issuer to see if it's them that are declining them for use with iTunes ? Or are iTunes gift cards available in your country, if they are you could potentiallyuse them to pay off what you owe