I would change all email addresses, and telephone numbers (or block her email addresses and telephone numbers), and then you don't have to worry about her contacting you or your H. I wouldn't write her a letter. It would just send the message that her emails are being read, and having an effect.
Take care!
Me:57 H:52 M:28 Got another lawyer last year and filed. D35,S/D twins28,D22 EA4/04 End? Who knows? "Life is like a mirror. Smile at it and it smiles back at you." — Peace Pilgrim