Banned...?

Hi i was wondering if anyone else was having this problem but lately everytime i FINISH a match of arena i get banned for no reason? Any explanation? I play normal and dont quit but as soon as the match ends it says im banned. This time for 2:30 hours.

For whatever reason (quitting, idling, disconnecting, etc.), your recent matchmaking record shows a number of unfinished games, which likely caused your ban.

2/4/2016 - 5 DNF
2/3/2016 - 1 DNF
2/1/2016 - 1 DNF
1/31/2016 - 1 DNF
1/27/2016 - 1 DNF
1/25/2016 - 2 DNF
1/24/2016 - 2 DNF
1/23/2016 - 1 DNF
1/21/2016 - 3 DNF
1/19/2016 - 2 DNF
1/17/2016 - 1 DNF
1/16/2016 - 1 DNF
1/15/2016 - 6 DNF

> 2533274862181038;2:
> For whatever reason (quitting, idling, disconnecting, etc.), your recent matchmaking record shows a number of unfinished games, which likely caused your ban.
>
> 2/4/2016 - 5 DNF
> 2/3/2016 - 1 DNF
> 2/1/2016 - 1 DNF
> 1/31/2016 - 1 DNF
> 1/27/2016 - 1 DNF
> 1/25/2016 - 2 DNF
> 1/24/2016 - 2 DNF
> 1/23/2016 - 1 DNF
> 1/21/2016 - 3 DNF
> 1/19/2016 - 2 DNF
> 1/17/2016 - 1 DNF
> 1/16/2016 - 1 DNF
> 1/15/2016 - 6 DNF
> …

The thing is i never actually never QUIT THOSE MATCHES.