I am in need of name and address of this person so I can file a CH-100 Civil Harassment Complaint at SB County Superior Court.

i need a last name to file legal papers in court.

It's unlikely you'll get  a valid name from this phone number.  It could be spoofed.  You just can't tell.  Where could you get the required back-up data for a civil restraining order, if you can't be sure of the person's name, or even address?

Call could be coming from anywhere.

At this point a call blocker might be your best bet.

Also, if you are getting threats of a criminal nature you should go down to the local police department.  Requests for a civil restraining order require a lot of information.