Itunes billing question?

If this is the incorrect forum, please redirect this question. Thanks! Okay, so I usually pay with giftcard\debitcard things that you can get and put a prepaid amount of money on them because they're much easier to manage than itunes points in my opinion (obviously I was wrong). So I'm sure many of those that do use prepaid debit cards are aware of this, when you buy a song it will instantly start downloading it if you have a credit card as your method of payment and then put the charge on later. But if you do not have enough money when it charges your card, it will simply put a debt on your account. Now I had a 5 dollar debt on my account because of this and a couple days later it was gone, I can't recall if I had put an itunes card on the account at the time (would that have cancelled the debt?) but I don't know it kind of worried me.


The Watered down question: Obviously I don't want to exploit the payment system in any way, so I just want to know if there are any unpaid debts on my account. Is there any way to check this?