I've only read her text and your proposed response. From that info I would agree with those that say do not respond.
I feel the abuse coming from her text. Rough stuff. I suspect lashing out like that seeking feedback from you. To not respond in situations like that, and better yet, to not feel the need to respond would be much more empowering for you. I don't know what your past patterns have been, but if your current responses aren't working perhaps it's time to stop responding.
OK I went back earlier, you may want to hide her on FB or unfriend her. It's not helping you.
You still seem close to the situation. She's still able to affect you. You've left open access for her to reach out and slap you in the face whenever she wants. You don't want to need anything from her right now and discussions it would seem best to remain minimal and strictly business.
Take care of yourself.
That's my reaction to what I read. But Like I said I have a limited basis for understanding your situation.
