(Crash)Game crash

I entered a ranked game today and after the game started the game didnt responed... I tryed to quit it or something but i couldnt do nothing. I Even didnt saw my mouse at the desktop when i alt+Tab (I saw it only near the windows sign). So i restarted the computer and then I got leaver buster... I want to get gold and now i have to wait 20 min for 5 games I dont think thats fair, i have only more 9 days to climb to gold and im on 0 lp after this game and if i will lose i will be demoted to silver 2. that was really bad for me is there any way to cancel that leaverbuster? I really want that skin for maokai. It never happend to me before...