Can you have your lawyer send a letter of cease and desist to her to stop the online smear campaign. You can google a case in Cincinnati OH where this woman was found guilty of telecommunication harassment.
www.cincinnati.com/story/money/2015/11/09/no-verdict-yet-indian-hill-real-estate-case/75445670/I would take a photo of the screen shot of these smear notices for future reference.
You can also call the 3 colleagues who received the smear letter to clarify things with them. If they are your friends they will understand and disregard the smear campaign.
Lastly, after savings all the nasty texts and emails. Don't respond to her communications, and don't even read them. Cut the cord completely, After a while of seeing no response, she hopefully will go away.
I am sure the letter of your attorney about the cease and desist is a strong indication from you that you will take severe actions.
Just cut the cord with her COMPLETELY.