He doesn't want to talk, so he chooses a "mute" button. And that's the line you see.

This guy is not the person I am playing against.   This guy is speaking french and is saying I keep chatting with him & he is very, very mad about all this!   Is there a button I might have pushed or something to cause this??

That circle and line are the "do not disturb" feature that subscribers can select.

He might just be a nut. Ignore him. Everyone has that button at their disposal.