Is this on a new game? i had the same problem and contacted the game manufacturer customer support, they sent me a new code, fixed the problem. Only issue is you have to wait however long it takes for them to hook you BACK up before you can fully enjoy the game you paid for.
Welcome to the forums!
Try to redeem the following code: RPPB-QFNJ-DBF7. (It is for Playstation Home content, and it is multiple use, so it should work).
1. If you manage to redeem the code above, then, there is a problem with your game code, you should contact the developer, or Sony for a replacement.
2. If you did not manage to redeem the code, please wait 24 hours, and retry to redeem your code (Make sure you type it absolutely correct).