I have completed the tutorial 2 times undownloaded and re-download my game and tried everything. When I try to go into co-op it just says checking permissions then goes back to the main screen. Seems like paying 70$ for half of a game! !)

I'm having the same problem with the PC version. I have submitted multiple forms trying to get some technical support, and both have been ignored. I've even tried opening ports on my router, etc, with no results.