Private Messages

Recently I played a normals match with a VERY toxic player on my team, and I was playing Draven for the first time. This player was my support and he was AFK under tower for the first 10 minutes of the game, and it caused me to die two times, in which he flipped out saying i was garbage and he had lag issues, then he started intentionally feeding and telling everyone in /all chat i was toxic, and the game ended at 20 minutes. After the game, however, he did not stop, so i simply reported him and left, he then decided to get on his several other accounts and add me, then spam me with very offensive comments and explicit slurs and continued harassing me. I now have 10 accounts in my blocked list, but I am having a hard time believing that's the only punishment players like this individual will receive for these actions. There is no way for me to report him for this and I am very confused and concerned about that.