Solution for your Unexpected Rank / Stats Reset
Have your stats, ranks, unlocks etc.. been rolled back or reset unexpectedly? If so, you can safely put your panic to one side. This is a well known bug that has effected many users on this specific Call of Duty title and Activision are aware of it. They have a page you can visit to start the process of having all of your hard work restored to what they should be. Activision are asking for one business day to remedy your roll-back or reset.
Click on THIS LINK and then follow the instructions on the page to start the process.
Please note that your stats will only be restored to what they were, prior to the reset or roll-back. You will only qualify for restoration if you have legitimately been effected by the games bug. Your stats will not be restored if you have been reset due to cheating or boosting. I hope this clears a few things up and helps any effected users.