I am having the same exact problem. Can't seem to get any help from anyone. Tried calling tech support. Recording said that there were too many calls so support line is now closed WTF????
I finally got through to tech support after about a half an hour, (33min), the said to get all the maps because there are servers for each combo of maps. I had map pck 1 and 4, it seems to be a very unpopular combo.
I reluctantly got the others to see if that would be the end of the problem, but no.
They also said to try port forwarding, witch I did, and that didn't help.
I short Activition has no real solution and does not want to act responsible for their mistake.
This is the way bussiness is done these days, get used to it. Activision, YOU need to fix this not us. I am NOT buying anything from you again unless you take responsability for YOUR
game ad-on's shortcommings.
So the answer to your question is, you are screwed yet AGAIN.
I'll get the same thing every now and then I think it's do to regional matchmaking. Since BO2 come out I have a harder time finding games in hardcore mode, not enough local people playing. If I do find a match it's with the same people everyday, need an option of getting out of regional matchmaking.