Excessive on the Perma Ban much?

So I was playing a game with some friends and we were getting rolled (our entire team) and both of them kept DC'ing so the obvious solution was to ff and straighten their internet out and get in a new game. Well they think its funny to mess with me and refuse, so I started getting on them as any friend would. Now I'm all for playing behind but there's a limit where the game is just too far gone, welcome to look at match history and see if matter.

After the game finally ends. BAM! perma ban flashes up on screen with the log of that game. From ONE game? Are you serious? As far as I can recall I've not once had and suspensions/chat bans and know with certain no bans. How on this Earth does one get permanently banned from a single game, and considering that the chat wasn't even that bad compared to what is seen in 90% from other people? I'm completely dumbfounded and appalled. If it was just a chat ban for few days, sure I would have just said whatever and laughed about it and gone on. But a permanent ban??? I've had this accounts for years and have been active playing and purchasing since start.... had over 1k RP that I JUST bought the other day too.

So question is where and who do I need to talk with to get this straightened out and hopefully at least downgraded? I'll accept the fault and take the punishment if deemed necessary but from personal experience I don't see how this could result in a permanent ban.

Below is the popup upon signing in- (1/3) http://i.imgur.com/Zo7bnkL.png (2/3) http://i.imgur.com/NYXAQ8l.png (3/3) http://i.imgur.com/iOWBnwH.png