[Kaguya]

I've had to deal with this in the past from my ex.

If she is being abusive through messenger keep the logs, every time she calls take a note of the time/date/how long the calls lasted and a summary of what was said, it is just stronger evidence that she is doing this... If you can record the conversations I'd do that too. If she is contacting you through email/skype abandon it or block her. with your cell or home phone you can block her number or even change it.