+1 to chat mute, but also to votekick in 3v3 and 4v4. I mean there is nothing you can do when a griefing teammate starts attacking your base...
Well if it helps: you can upload the replay and also make a screenshot from the action and he will get a timeban.
Wouldnt even surprise me if it was someone who got banned on .org in the past.
Look at his profile now xD
If it really bothers you, and you did not do anything to make it worse:
1) Save the replay of the match.
2) Upload the replay here(see REPLAY MENU).
3) Make the title "FOR STURMPANTHER".
4) Describe who was saying bad things and about what time. Sturm is busy and does not want to sit thru your whole match. So the more you tell him the better chance the person gets banned from the game. So say something like RedRocket was BMing me at 15:30.
But you don't need to give the time for chat insulting/ racism etc when its in all chat. Because i can see the whole allchat on org
If it is in the teamchat, you need to make a screeshot, since I can see only allchat.