I always say (often to myself) that I as GM am not the perfect GM for every player that I meet, just like I as a player, not every GM is the perfect GM for me. Sometimes it just doesn't work out, no matter how much work gets put into the relationship. Being online just makes that problem worse. Sounds like a rules lawyer player, who needs a similar GM to be happy. One question for you, though, has having this player in your group helped you learn the rules better? When I get the rules lawyer type at my table, I often respond by learning more about the rules of the game, so that I can say "that's the rule" or "this is how I am house ruling this", whichever applies. Maybe help the player find a GM that is better suited? Don't know if there's a good answer to your situation, but there is an answer somewhere.
Good luck