Getting flamed all game and added after game for more flame

Last game our blitzcrank flamed me hard the whole game, it was really annoying but I don't really bother to care. After the game he added me (I didnt know it was him) where he wished cancer and car crashes for my family. I got a good laugh and don't care but I got some screens and would like him to get banned since next time he might attack someone who's more sensitive than me. Also, am I allowed to post screenshots of the convo?