(Failed To Choose Champion) I Locked In. Now I Have Leaver Buster.

Ok, So I get on to play and I join a game of blind pick. And I join in call my lane (top). I lock in. Then when I think the game is about to start I get kicked and it says I failed to choose a champion. When I know for a fact that I chose my champion and locked in. But now I have a leaver buster that is what, Like five minutes and forty seconds. This is bull crap.