I went to leave a competitive match because the teams were very unfair but it said my account will have a penalty. what will happen? but after that my game just “crashed” 
What happens if you leave a competetive match
_Havoc
(*Havoc*)
#1
Vexed
(Vexed)
#3
Well it won’t let you play at all until that match finishes, instead insisting you reconnect. It will probably also do things like keep track of how often you do it and make things difficult for you in other ways, but the details are likely kept sketchy to stop players getting a good feel for how much they can game the system.
Also, I don’t see why you think forcequitting will fool anybody. Penalties for forcequit/disconnects are a thing in basically every game with a penalty for quitting.
Draza
(Draza)
#4
Hi! Probably a little late, but here it goes:
As Vexed Said, you’ll have to return to the match if you leave. But if you can’t (or don’t) return until it finishes, you’ll be temporarly banned from comp ( you will still be able to play casual).
I was banned for a day cause i lost connection, but maybe you can get banned more time, is still dont know(and dont wanna lol)
Hope I wasn’t too late 
kibloy
(kibloy)
#5
This is the only official info I can find, not sure if it’s still accurate. Scroll down a bit to ‘What triggers a penalty?’
Phukka
(Phukka)
#6
Get banned for a week! So pathetic leaving Comp because you’re losing! Stick to god-damm Pub, no? So bored of people like you who leave games because they sulk for whatever reason.