Hi there..
I can actually empathise with what your going through right now as I went through a similiar experience, about 5 years ago now.
I know how afraid you must feel and it is at times frightening.
Firstly the safest thing to do would be move/house even city, this is what I was told by the victim support unit and it helped me immensley.
If at all possible try not to live alone, find someone you could share with as it not only helps you to feel safer, but it does actually intimidate your ex from stalking you further.
Then I took out a trespass order so if he were to come within a certain distance of my property I could have him arrested.
Empower yourself girl, this is a power trip for him and he is loving it.
Change your phone numbers both cell and land line, but give these numbers only out to your most trusted and loyal friends and family and explain to them that under no circumstances are they to pass these on.
Keep your number confidential and unlisted and same with your new address.
You can then press charges if every other avenue has failed you.
Good luck to you!!! as I do know it is difficult but I have every confidience you will pull through this.