Billing Loop?

A few days ago I went out and bought a prepaid VISA so I could buy some apps in the iTunes store. (You can’t buy apps with an iTunbes gift Card in Canada) I spent it all on apps and then with the tax of the apps i ended up owing some money. I also can’t download free apps because it says there’s a problem in my purchaise history. I seem to be having a similar problem to this person. (“I’m having almost the same problem. I was using a prepaid credit card and the balance wasnt enough so i bought an itunes card and I got to that same billing info problem. I tried all other methods, and even removed the credit card so that all I have left is the itunes card, but when i try to pay with it, it just refreshes the page and never pays for anything! Please help someone T_T)” If anyone could help it would be great. How do I stop this. I want to be able to download free apps :(