Sorry to hear about that, but could you please send me a private message with your information so we can assist you? I'll just need to know which version of the game you purchased, which exact DLC you are having issues with, your gamertag, and also a screenshot showing proof of purchase. Let me know and I'd be happy to assist. Thanks.
Same issue here, bought the Ultimate Warfare Edition of the game last night and am unable to use the DLC I paid for. I uninstalled the game, cleared the cache, and reinstalled it only to continue having the problem. The site here doesn't list the game itself so there isn't a clear path to getting help. Very disappointed
Im Having the same issue i bought this game today on sale and i cant use my DLC