Need a champ select player ban or report method

I have had many games where a person has said he was trolling before the game, trolled in the game, fed and didn't help team, purposely picked a bad champ for the roll and pick bad items. I have had people pick into lanes that are already picked and say too bad duo, or who will say i'm following x person and stealing all their farm then feeding. then in the game the 90% of the time follow through. you need to implement a ban/kick/report system for the champ select lobby to prevent us from having to play with people like this or leaving the lobby and getting banned for it and losing LP also. this happens all too often when people say they will feed or say they are going to troll and we can do nothing about it besides lose a game, lose rank, and report them after the game. This still leaves us with all of the penalties for this person and the odds of everyone reporting him are slim. they are too angry that after they game they immediately leave the lobby and don't report.