Harrasment. . . WWYD??

princesa2423

Lurker with yet another q . . . 

 So currently going through the divorce process (ugh . . .), and only allowing STBXH to have supervised visits with DD for now because she isn't very familiar with him and is going through that separation anxiety, and because he has been very unstable (anger outbursts, history of domestic violence, etc). The judge is sending us to mediation so we can work out custody and visitation issues. However, now STBXH's g/f is harassing me via e-mail. She's sent me two VERY insulting e-mails (from his e-mail address) about how I never knew how to be a wife, am a bad mother, self-centered (none of which are true, my DD comes first in EVERYTHING). They have both proved to be very unreasonable and unyielding, so I haven't responded because I'm not looking for arguments, or that back and forth stuff, I have better things to do with my time and life. I'm just curious, what would you all do in this situation?