It was a control game on asylum
I was using praedyths revenge and killed all 6 of them as the came up the steps towards the room where b is right at the beginning of the game, probably like 20 seconds into it.
They were a lobby of 6 and sent me a message saying reported for cheating by 6 people, along with a screenshot of him reporting me. I kicked their ass that game and they backed out during the countdown timer and the guy blocked me as well