Yeah I got the same problem with a mate who I played Defiance with. He kind of went awol and we haven't played anything since lol I was able to chat to him to make sure all the copyrights to the intro and outro music was all good but he hasn't contacted me to play anything, he's still around up to stuff here and there. This is why I've come up with a rule that I will not release footage of a playthrough with a friend unless I have 3/4 of the game recorded. For good reason too, because my mate Loopy has exams and stuff until the end of Nov so he can't play GTA IV with me until then. Fortunately I have enough GTA IV footage to last for another 2 months
I just need to edit it all >.> As a result of him going awol I had to release Dead Space 3 as a mini series instead of a full series and I had to put Defiance on hold for now.