Leaver busters

Oookay lemme say some things real fast. A moment ago i was in ranked game and my net got off . I was thinking it was something cuz of my net but i saw like that ranked is disabled. After the game i left because of my net and i got leaver for no reason. I remeber that if you leave twice you get leaver but.... why did i got leaver can someone explain me this thing. And why did it got of my league points ?