we need to bring permabans back

I just played with a summoner() in ranked that intentional made my team loose to drop his/her mmr for the next season. This player played support and farmed my jg and lanes, revealed team doing objectives so we couldn't get them and fed. This player made the game not winnable and has done this several times before. I hope riot deals with this matter, because it represents a terrible side of the game. This was just one game where i had this experience but has left me with a bad experience that towers over all good experiences. Please review game history and premaban that acct.