What is wrong with my Apple ID?

I bought a couple apps out of the App Store and Apple sent me a receipt. Or what I believe was a receipt ( it said receipt!). Anyway, after I buy apps I check my card to make sure it took it off ( I use a prepaid card). Everything was fine, I could use the app and all, then one day I try to download a free app. My iPhone tells me there was a billing problem with a previous purchase… But those two apps are the only apps I have bought and they both were deducted from my card so… Any other app I had was free. I don know what's wrong and I don't want to have to pay for it again. So I guess my questions are was it a free App that charged me? Am I being double charged? Or can you buy something from iTunes without any form of payment and have it billed to you later? Oh and um how long does It take for them to take if off your credit card, can they wait like a week before they charge you? Until this is fixed they have barred me from downloading anything…

This sounds like the sort of thing you need to sort out personally over the phone. Give Apple Customer Care a call. It's not something that anyone here can tell you how to fix, as it's a problem with their billing system.