I had one of the people who sexually assaulted me as a child invite me to be his friend on facebook, randomly decades later. Feaked me out.
I blocked him. Or thought I blocked him but all I did was decline his friend request.
Then I saw him comment on a school friends profile so knew he was still around and I hadn't blocked him. Then. I worked out how to block him.
So now, I don't see him in Facebook.
So: block him?
Change your social media name?
You don't need to communicate with him at all. Sometimes contacting someone to ask them not to contact you, is what they want? It's contact. It's communication. They know they have a reaction. But blocking. Not telling them anything but just doing what you need to, they have no idea about you, your feelings, your motives, your actions.