Why should she got to that much effort to prove to someone who is no longer in her life, that she is superior to him? Why fall to his level? Whatever he is trying to do or whatever mind game he is trying to play, best is that she makes it clear that it is not affecting her. If she replies, it will be like she has taken the bait! She is again in a war/game with him. She should just bloody ignore it and move on. It’s just a freaking text message.