How do you report someone out of game?

So there are many threads with this topic and all of them end with the conclusion to send a ticket to Riot's Support desk, however I looked at the categories for the tickets and none of them even came close to what I need, which is to report a player who is openly toxic and queued into a game with the intention of trolling which he openly admitted. Additionally he also banned the champion I was going to play simply stating "I hate Yasuo" and since I am a low elo player I shouldn't be allowed to practice him in a normal game. Only when I asked my team to report him after the game did he realize that this attitude was going to backfire and come with real consequences and he promptly dodged the game. I have several screenshots saved showcasing the whole conversation but I need someone to send them too. I would like for this person to be punished for their toxic and juvenile behavior not just because it offends me and ruined my gaming experience but because I am sure that I am not the first person they have trolled and unless something is done this person will continue to destroy the fun of future gamers and pull down the league community with their toxic, immature, and frankly predatory behaviors.