Did you double check to make sure you have the right code? Sometimes zeros look like an O, for instance. If you're sure everything is entered correctly, you could also try entering the code again. The codes don't always go through on the first try. And if you can't get past that hurdle, you can also try getting in touch with GameStop or Sony to see if there's something that can be done about this. If the funds can be added to your wallet over the phone, then that would certainly help.