I've got used to chat restriction system being a complete joke due to it being triggered by blacklisted words that often have no negative meaning in the context they are used. But applying a ban (a matchmaking ban) for no reason whatsoever? I've just played my 2nd ranked game today, in first game I haven't performed well but my behavior wasn't "disruptive" as it was stated in the recent ban reason. Next game was quite a stomp (enemy has disconnected after a few deaths) and yet, I've got a matchmaking ban after this game.
Fix your damn system. If you're applying bans then at least let them be for some REAL reasons, not imaginary ones.
Also the chat restriction periods make no sense. User has no feedback when it's present and for how long it'll stay. In game chat block? Whatever, but at least let people communicate in champ select screen.