This is the second reproval by you which I find unacceptable. It has been noted that she is a "neighbor" a friend of yours and a chatmate all of which is fine but apparently you are receiving only half of the communications. If I were you I would withold comment pending receipt of the entire picture.
I would agree with you that the exchanges resemble schoolyard taunts and I'm more than willing to end it albeit not on amiable terms Being called a coward somehow doesn't sit right with me and I will not tolerate it.
That being said......flameout is acceptable, at least from my perspective. By the way, you want offensive, give me your email address and I'll foward what I consider offensive authored by your pal.

Oldboldpilot36@protonmail.me