To report someone go to their profile page and at bottom is a link to report. Anything that happens in-game (chat, game name, player-names) can be later seen under "past games" where all links are availabile
If it happens in game room-waiting, then the link dissapears: for example if game won´t start or gets deleted. So next time just make a screenshot and post hosts profile link like yours: https://www.warlight.net/MultiPlayer?GameID=908867
Why it is better to post link? Because if one changes name, it might hard to find him, but link is passive. And if you wish you can blacklist a player, so you wont see their made games nor can they join yours!
Edited 7/13/2015 12:54:48