Joke of a report system

See, I'm not normally one to report people, just not me, but today i changed that. This darius in ranked that i played with asked me to swap my jungle spot with him for top, i said no because i don't really like top that much, and he put top in his choices. He spent the rest of champ select flaming me and the others because i wouldn't swap. Then went into game telling the other team we were all toxic (we were just telling him to play top, nothing really bad) and here's where the fun started. He ran down his lane multiple times and intentionally fed illaoi, he even said "just kill me" before doing it a few of them. After going 0/8 he started spamming emotes in fountain, then as they were on our nexus at 17 minutes he came out and legit started playing, getting 2 kills and 4 more deaths. 7 people in the game reported him (thats how many said in post game they did) including me who wrote a legitimate paragraph about this guy. Know what happened? No message saying he was banned, and no punishment for the guy who spent all his time flaming us and intentionally feeding in ranked so he could get out of the game instead of dodging. How some people get banned, but no this guy, is absolutely beyond me.