Heres the thing man.
First off, your friend, if you said anything like that in retaliation, it doesnt make you any better, so of course your gonna get punishment as well.
If you're in a bar fight, some guy walks up to you and dumps his beer on you, and you bash his face in, and you go to jail, of course you do.
Same thing here just on a lower degree, just mute people, dont type, no one is forcing you, you blowing up like that is what trolls want.
Secondly, If your account MMR is bad, even if you quit for 2 years and come back, your still going to be played with those shitty players. Make a new account and try leveling up and playing your best, and do not even dare say you are a smurf. Once you hit lvl 20, get your runes, grind out lvl 30, and play support and try and get gold off your first 10 placements.
Sounds stupid, sure, but ive done this for my uncle on his account over thanksgiving break, hes 61 years old, one eyed guy who never plays ranked and only plays custom games, i said hell with it and tried ranked on his account? Best 10 games i have EVER played. (Note this was in pre season for Flex Q and NOT in normal season, so i didnt really boost him :p).