I'm writing this Tech support thing for my friend KemistLinus, because he can't log in to the forums for some reason.
Match ID: 93092666
We were playing along just fine when at 16:10 ingame time he was suddenly terminated and disconnected, in that order. He was returned to the main menu and his "Play Now" button was grey, so he logged out and logged in again. No reconnect prompt was shown so he tried to connect by "joining" me. This didn't work, and instead he was shown a message that said that he had allegedly waited over 5 minutes before reconnecting, and that he had been terminated because of that. He later tried to mentor me, and that also failed, it said that he had tried to reconnect too many times for some reason. We proceeded to lose the game and KemistLinus lost 10 mmr for that game, and he also got a leave.
I hope that you can give him back his 10 mmr, and revert the leave that he got.