If someone adds you after a game to talk crap about you, can riot see those chat logs?

So long story short, I was {{champion:51}} , my duo was {{champion:555}} , a {{champion:238}} player got angry at my duo being toxic, when i had all chat disabled (i do that so i dont get tilted), and then he added me after i said i hate toxic players since he and his team were bming to talk crap about how my duo was being toxic and i didnt say anything, even though i didnt have a clue he was being toxic. this led to him admitting to being toxic, saying he wanted to annoy me while im ingame, and etc... Can someone from riot check chat logs? If so, how do i report this guy to them?
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