Trolls and nothing we can do

I try really hard to be a good player and i usally dont flame. Yes i tell people if they suck or there bad but what can be done about draft pick trolls in ranked games. Im stuck in bronze ( yes im sure i could do alot to play better) but i shouldnt have to carry the whole team every game to be able to get out of bronze. This morning alone my whole team fed, next game anivia insta locked mid after some one already chose the champ and called it in chat. once we where in game they hijacked mid, so mid went to bot to support me as the adc, anivia then hijacked top and the top went mid to try to make the game work. As always these trolls screw up peoples chances of being promoted just to be dicks and lol does nothing about it but give generic responses of how they cant say what there doing to the champ for privacy. Trolls are ruining lol and im at the point of streaming anothing game. For the love of god do some thing about the trolls because its out of hand and the good non toxic players cant enjoy there game or even progress because of them.