doin, so sorry things are so bad :(
You sound like you are at the very end of your tether.
I have experienced the taunting and being followed around and having things snatched too. It is terrible and frightening and infuriating.
I have also experienced being 'rejected' by CAMHS and counselling and social services, because DS didn't reach their thresholds. It makes you feel desperate because you need help but you can't get it.
You can take some control in this situation, doin, really you can. You need some space and distance from her, urgently. You can't control what she does, but you can control what you do.
You have some choices...
I also think you should phone social services and tell them what you have told us. It might not be enough to get their help, but it might be.
Is there anywhere you can go for a day or two? Your DD is 14 and she will be fine over night on her own, but if you want to make sure she has some 'backup', tell someone in your family or 'phone SS and tell them you are going away and why.
If you feel unsafe, or she hurts you, or you are scared you will hurt her call the police. Seriously. I dialled 999 three times with my son. The third time I had him arrested. It was terrible, but it was less terrible than the way things had been. And he has not been physically threatening to me since.
Is your DD back home? If not, then make the most of the breathing space you have now. Do something to help you relax. That is the first step. If you are panicking, you won't deal with things well.
Things are really bad now, doin, but they will get better.