Connection Issues? Help please.

So here's my problem: I'll get disconnected from the Black Ops II servers and Xbox Live when playing solo.

Whenever a host migrates or the game rebalances teams often, I will receive the "Call of Duty: Black Ops II servers can not be reached" and then "You must be signed into Xbox Live to play online." Shortly following that I get Disconnected from Xbox Live.

Ironically, if I play with friends, I'm fine.

I have contacted Xbox Live support but they seem to be of no help. My NAT is completely open and I have a wired Ethernet. I have re-downloaded my Gamer Profile and cleared the cache.

Any solutions? Thanks.