Why does my debit card get declined?

I have an iPhone 5 and I've had my debit card linked to it for months and I've had no problems with it and I day I tried downloading a free app but it wouldn't let me cause it said my card was declined. What happened? I tried putting my info in again but that didn't work.

Have you ever disputed a charge with iTunes? Maybe a charge that you did not recognize. If anything like that happens, the card on your account has to be removed and a new one has to be added. You can go to expresslane.apple.com, click on the big blue thing that says itunes, then pick itunes store, then pick account billing, and then pick purchase declined. It will ask a couple questions and then after you answer them pick the Chat button and you can talk to itunes that way. There's not a direct line and the only way to get them on the phone is to go through either the iOS or CPU department. But the rules changed recently, and now if you call we have to refer you to that website so there really is not any point in calling until after you talk to the Chat Advisor.