Shaun90, I can truly identify with your anger and frustration. It doesn't matter what her family does, or does not know about her behaviors. The issue, here, is that SHE does not care. She doesn't care. She never has, she doesn't today, and she never will. That cannot be altered, changed, or epiphanied away. She is what she is, and she will only change if she makes it happen.
Contacting Social Services will not make her change herself. Social Services is a very, very broken system. The current stance on taking children away from their parents/guardians is that "...children should remain with their families..." even if one or both adults are dysfunctional. There are not enough foster families and many of the foster families are just as bad (if not, worse) than the children's families of origin. Social Services is not the dedicated individuals that fight for the rights of children that we see in television and movies. The case-workers are tired, overworked, underpaid, restricted, under constant scrutiny, and must make decisions based upon the current day's political climate.
And, calling anyone as an act of vengeance is not good karma, I promise you. What goes around will come right back around.
How to deal with this situation?! Talking to this woman only creates anger, confusion, frustration, and anxiety! What to do? The answer: walk away. Disconnect. "No Contact," under any circumstances. This means blocking her number from your cell phone. Blocking her profile from any/all social media apps: FaceBook, Twitter, and whatever the hell else people are using to "communicate," these days. THEN, one must do the same thing with all of her family and friends, including mutual friends - anyone who will tell you what she said, what has happened (today), etc. Any and all inroads into your psyche and life must be cut.
If she's as crazy as you describe, take out a restraining order against her so that there will be LEGAL consequences if she chooses to defy the terms of the restraining order. This will not only protect you, but it will also set up a precedent that she is disturbed and dangerous in the event that Social Services does, indeed, become involved in her life. The caveat with any restraining order is that the plaintiff (YOU) must never, ever break the terms of the restraining order, either. If she calls, you don't answer. If she sends an email, you copy it, give it to the police and DON'T RESPOND. If she has a friend contact you on her behalf, you do not respond and tell the person that they are violating a standing restraining order. This is "No Contact" at its finest. If you break the Restraining Order by any response or acknowledgement that she has contacted you, then it becomes VOID.
All of this might seem really extreme, at first glance. But, there is a behavioral dynamic in this situation that has all of the hallmarks of a serious mental/behavioral disorder that has no means of treatment.
The more you learn about sociopathic behavior, the more that it will resonate with you. There are varying and infinite levels of this behavioral disorder, but it boils down to this: no conscience, no remorse, no empathy, and no compassion. They do what they do because they CAN, and they simply do not care (are not concerned) about whom they hurt or defraud or abuse. They don't and it's a very challenging fact to process and accept - that someone that I once loved and cared for never did, at any time, care about me.
So........it's going to be a challenge, Shaun90, but this is up to you - to either turn your back and accept things as they are, or not. The former is sad, difficult, and painful. The latter is all of those things, times 10, and more.