Over the past three days, i have been matched with the same troll five times

Every single time i see him in game, he actively sabotages his team by troll picking, constantly running into enemy champions and fighting to the death regardless of how he is doing in game or the position of teammates. My first game with him was against him and he single-handedly pulled his team down, the next four he was on my team.

Every single game, i have reported him for intentional feeding (intentional feeding, griefing) and negative attitude (griefing, calling "ff" and spamming surrender votes from around the 7 minute mark every single game.) I still keep getting matched with him over and over.

Why? Why am i still getting matched with him? Why hasn't he been punished when this is what he does every single game he plays? Why do i have to keep being matched with him and keep losing games because of his toxic behaviour and careless playstyle?

EDIT: Six times and counting, because after writing this i was matched with this player again - this time on the enemy team - and they pulled their entire team down once more, frequently walking into other lanes to afk next to enemy champions without even fighting them.