I just read this. She was sooooo wrong in starting this email exchange with you to begin with. What is wrong with her?? She had no right to ask you for confirmation that you received her termination letter. That was just an unconscious ploy. I know it doesn't help you to know she was effed up, and that she is so totally mishandling this right now, but all this cannot be handled by email. She is being not just ridiculous, but unethical.