Report system is sooo bad

How does someone lose atleast 443 ranked games with a 0%-1.2% win rate on Tahm Kench, Trundle and Nunu, but then has a 100% win rate in over 330 ranked games as Master Yi. If you want to watch a video explaining this heres a link https://youtu.be/BQ5LXCMwZP0 This truely shows has the report system has severe issues that NEED to be fixed. Here is a link to the players profile match history http://www.lolstarz.com/summoner?name=Elave&lo=kr He hasnt played in 3 days so hopefully his account is banned, but seriously over 440 purposely losted ranked games before he got punished, thats ridiculous and should never happen.