Hey there again @bigkitty420
Oh hamburgers.. That sounds to me like Gamestop has goofed and gave you a wrong code. Unfortunately, as far as I know, there isn't much we can do to that here. You need to contact the Gamestop for that as they provided you with the code.
I would either go to the Gamestop store where you ordered the game from personally and explain the situation, or I'd take a call to their customer service : http://www.gamestop.com/gs/help/contact.aspx
If you aren't residing in the US, here is also the international link to Gamestop's site : http://www.gamestop.eu/
First click your region. A red speech bubble should appear with greetings in your local language. Choose the "Visit site" option on that red speech bubble. This takes you to your region's Gamestop page. Scroll down to the bottom of that page and you should either find the contact number there, or some equivalent to "Contact us" from where you should find the local contact information to your country's Gamestop services.
With any luck you'll be able to get yourself a new code if they can confirm that they have, indeed, given you a wrong product.
Good luck !