Start documenting everything. If he is sending you texts or calls, you need to block his number, contact the phone company and make certain that you're doing it correctly and that all of your privacy controls are in order. Privacy controls on all social media are essential. Please makes sure your google tracking is on lockdown. You need to be diligent about everything.

THEN you contact the police and discuss the details obtaining a restraining order so you are ready to do it if you have to.

If you haven't already and only iff he contacts you again, state very clearly: "Do not contact me again." Let that be the last communication. Period.

The main thing is not to respond at all, ever to any of his attempts to get a reaction or connection, even negative connection, with you. Stay safe.