Need help stopping cyber stalking

I don't know what to do to make it stop. For the last two years I've been the victim of stalking, harassment, defamation, etc. via proxy email, fake snapchat accounts, and globfone texts/calls.
The person has contacted employers of my friends which have resulted in multiple work and HR problems. They've sent messages attempting to ruin relationships, telling my friends to kill themselves, and trying to isolate me from reaching out for help.

I've never received a reason for any of this…

Need help stopping cyber stalking