I just got the same toxic player in two ranked games. They've been doing this for over a week.
In the first game, they picked Ezreal for the first time and did badly in the early game. They then decided that Ezreal sucks and they don't want to play. After refusing to surrender, they ran into the enemy team three times, and finally just went AFK.
In the second game, I only spent about 40 seconds in queue, and I had waited a few minutes after the last game specifically so I wouldn't get this player. After a while, they decided they didn't want to play anymore and did the exact same thing as the last game; we refused to surrender, they intentionally fed a few times, then went AFK.
This specific player also has eight ranked leaves over the past 7 days and were harassing the enemy team throughout the games I had them in.
Why is it taking so long for an obviously toxic player to be removed from the game? This player is literally hitting every possible behavior they could be banned for, and they've still managed to get away with it for so long.
Also, why am I encountering this player in back-to-back games after reporting them and only waiting in queue for 40 seconds? There was absolutely no reason I should have been paired with this player after reporting them. If there are concerns about it being abused at high elo, put a time limit on how long you can stay in queue without being matched together and only persist the block for the next game. This isn't an unsolvable problem.