..What is an Apple ID balance. I was trying to load (redeem) $50.00 to my I-Tunes music store account to buy music.. I put in my numbers from my recently purchased card, but somehow my I-Tunes is asking for a mode of payment to purchace music

Can some expert on this planet help a novis Apple i-pod user...:

Why am I having problems downloading my recently purchased redeemed card.. when in my account there is my $50.00 appearing in the Apple ID Balance under my account summary.. Did I download my card in the wrong section or dept when I tried to buy some more music? it's almost like I can't use my money to purchase music... Plus when I go to my I-tunes to buy music with my $50.00 redeemed card it takes me to account information asking for a mode of payment when I already have $50.00 waiting to be redeemed.. I tried using my card again and it tells me the card has already been redeemed or activated..Can someone help.

Thank you,

USC Cinema 92