I can tell how hard this is for you from your post and I am very sorry you are dealing with this. Believe me, I know how much it blows.
The good news is that you have a job! You are meeting new people though your job which is also really good.
Personally I would not respond to the voice mail. I would go dark. But then, that's just my opinion. I struggle still on whether or not to return texts or messages. I do not check Facebook and don't comment on anything she writes. It's just too painful for me. I went cold turkey and blocked her, which of course made her mad. Oh well.
You keep posting on this Board, you have a lot of support here and have many many friends rooting for you. OK?! You can do this.