banned issues

So earlier i was in a game with one of my friends and we were playing aram this guy went in every time he came back and just kept dying i asked him to stop feeding and he was like "sorry I'm not poor i don't have all of my time to waste to get good" he was calling us all poor because we were doing good then he started to turn it around on us saying we were calling him poor. my friend said "aaaaand muted" because he didn't want to hear anything from the guy anymore. we get off to go eat we get back on 3 hours later and my friend got banned for not saying anything. and the week earlier he was in disney and he has got banned while in disney nobody was on his account he didn't have any recent games in his history i want to know what is wrong with riot not looking in the chats to see what is really going on instead of banning someone from a false report