Q: I can't download any apps on my iPod 5th generation because i keep being asked to verify my payment method and the games are supposed to be free ?

So I can't download any apps because i keep being asked to verify my payment method. The apps that i'm trying to download are free so I don't really understand why am I being asked for credit card information. I have a credit card that i declined but an issue never occurred , I believe its because I recently tried to use an awards card that can only be used by electronic use only. So later that week I tried to download a game and now I keep being asked to verify my payment method when i'm not supposed to be paying for anything. How can I change this saved credit card ? I would like to delete the information and not have a saved credit card account.