Q: I have $42.96 left on my iTunes credit card. The balance shows up on my home paIge but when I try to buy a song it won't deduct from it goes to my Paypal

I have a balance of $42 on my iTunes credit card balance. I'm trying to buy songs but instead of deducting from my balance it goes to my old Paypal account.. I don't use it anymore to buy songs but I can't find any help to let me use my iTunes balance. Where can I get some help??