Doxxing & Player Reports

Recently, a friend of mine (who shan't be mentioned here) Doxxed me in a matchmaking lobby of people neither of us knew in real life. I can't tell him not to do it again, because he is unbelievably stubborn, and says that it was perfectly fine for him to do so. I had no idea what to do, and I have put extensive research into the topic. I have concluded that there is no way to report him for it, which isn't fun for me at all. Is there anything that I can do about it, and if I can't, how many people would like to see this in-game?

As an added bonus for any rioters looking at this, reporting people a little while not on the "match end screen" after a game ends; e.g. 1 day after the match ends, would also be very good.

[zombie-brand-facepalm]