I received a code from xbox for a free ODST campaign for MCC. I tried to redeem it right there and it said the code had already been used. Ive tried every troubleshooting option so I contacted Microsoft support and after several days of working with them, I was told to come to you, the developers. I hope we can resolve this soon and I can hopefully get another code gifted to me so I can play some more Halo.
Check the MCC FAQ link in my signature, there is an xbox support forum you can post on that is specifically for dealing with compensation issues. If you make a post there someone should be able to help you. Unfortunately no one on the forums here would be able to help with your issue