First off, what console are you playing on? Also, I'm a bit lost now, bro. Are you having issues with your DLCs or with the freezing? If it's freezing, is it random or does it happen on a specific part? If it's specific part, where does it happen?
If you are using PS3, try deleting your game data utility but if you are using Xbox 360, deleting your title updates might help you. Also, try using different account if you will have the same problem.
A support case was created for you and you should be contacted shortly by a Customer Support Representative, if you haven't been already. You can view and update your case at the Activision Support website. After logging in, go to "My Support" then "My Cases".