Retaliation glitch thread
I'd try that first, and follow up with EA Support afterwards, if it doesn't work.
Edit: When I say "try that," I should mention that Grim never updated the OP with the possible fix that I suggested. I've never had the Retaliation Glitch since, so I haven't been able to test it, but try deleting all SP and MP DLC, then re-downloading and installing them again from scratch. Then, if that doesn't do the trick, try removing the Retaliation DLC (or all DLC as Saints suggests in the thread) by moving it to a USB according to Grim_AoD's advice in the OP.
Don't use contact@bioware (it's an unmonitored address) and don't use the answer HQ, use the actual EA support if it gets to that point (phone support from EA is actually pretty good, when I've used it.)