There's really only one way to successfully deal with someone like this: ignore them. It's obvious you two have nothing positive to share with each other, so the interactions are going to be negative. STEEMIT needs to be a positive place if you're going to make any money at it. So, my best advice - put down your gun & just walk away. It always takes two people to keep a thing going. Let go of your part. Sooner or later, the other party gets tired of beating on a dead horse, and they move on to someone more... interesting, to them.