promo code already redeemed! help!

the promotional code i received says was already redeemed. can a system admin please contact me regarding this issue. this preventing me from enjoying the game and leveling up further! any help will greatly be appreciated. as i have already contacted xbox support and they directed to me to this forum. i hope this is the right area to post or someone else has a similar issue. i followed the online instructions through the e-mail sent to no avail. thank you!
bobbyjoyce