step 1. dont respond to him, your just gonna fuel the fire and make him continue if you get angry and insult him, (your tears are music to his ears)
step 2. press "Esc"
step 3. click on mute player
step 4. find trolls name and mute said troll........
step 5. enjoy your day
for the love of god people, if someones acting up in chat, MUTE HIM, it makes things 10x less frustrating
and this is coming from a guy who gets muted ALL the time and frankly doesn't give a single fuck about it