Need help redeeming my xbox live code

[Charles Higgens]

I tried redeeming the code in my browser on my computer using these instructions, big mistake. It said "thank you, you redeemed your code" and then exited me out. No gamertag registration whatsoever. I thought the whole point of redeeming my code was to create a gamer tag, but no just exits me out. I then tried redeeming my code on my xbox (so that I could create the gamer tag) and it said "sorry, code already redeemed."

so what the... what do I do now?