I tried to log into my account today and got a notice that I had been banned for MMR boosting. I immediately sent a support ticket in and was told, that my account was banned for MMR boosting but didn't offer any context whatsoever. The only ranked games I have recently are flex games that I duo'd with friends that are also diamond on their smurfs which their is no rule against. I was silver in flex so we were going against mostly silvers, and golds.
Link to ban