Whenever I try to buy a app, I get a message telling me that my account info has changed and that I can't buy the app. My credit card hasn't changed, and my password is still the same. It only gives me the message when I buy a app, not when it's free. Any ideas how I can fix this? Oh, and short of looking at every one of my reciepts, is there a way to check how much money I've spent on apps? I think I've spent... "a lot".