I have just discovered that when i set the settings so that chat is turned of that chat seems to be always on. I did not come to chess.com to chat while I play chess. The only work around is to manually check every game and make sure chat is disabled.
Go to the Live settings on the website. There are two options related to chat: "Chat Requests" and "Game Chat". For each, select either "Nobody" or "Friends Only". Click "Save".