if you call xbox support, xbox live support department and tell them the issues your having with the online part of this game you will more than likely get a refund for the DLC as i just did.
I also mentioned that when i choose the Retaliation mode in the menus i can spend 5-10mins wating for a game, i told them this is unacceptable and as a result the game doesn't function as described.
I will point out though, make sure you speak to the USA team as the Irish team are totally arrogant and unhelpful.
If they don't refund you tell them the DLC is not working and that everyone is complaining on the forums.
I did all this and got a good result.
Good luck.
Oh, post here if your succesful !