Nuketown Problem

So I got the game this weekend and inside came the code to download Nuketown 2025. So I insert the disc and decide to download the map before I launch the game; so I go to redeem my code and begin downloading. At 4% of downloading my XBOX freezes. I wait and wait and nothing so I decide to power it down. When I turn it back on the download is no where to be found and the code is registered as already been used. What do I do? Who do I call? I'm at work now and will shortly be home where I have the game and the leaflet with the code.