Dead Island co-op issues?

[XxfreakaleekxX]

hey, Me and my friend bought dead island to play co-op but that's not happening lol. when we finally connect and join a game together we can only play for about 10 min then one of us will freeze or one of our characters will just be standing in one spot. My friend said that on his screen my character was just looking at a wall but on my screen i was moving around walking right in front of him but he couldn't see me. we were playing in the same game but couldn't see each other. is anybody else having this problem? and do the developers have a forum for bug/glitch issues? because i cant find it.