As many have mentioned your best to have your own independent survey done just to verify his information. Typically a property boundary marker is a 4x4 or 6x6 concrete rectangle with a hole drilled into it to make the exact property line. So get your own surveyor and then run a nice planting bed just a couple inches off the property (on your side) and then he can always see where the line is. If I were you, the next time he got into my face I would explain to him how nice it was when the last person lived there and how everyone works together and helps each other out. I always say "kill them with kindness". Tell all your neighbors to do the same...maybe that will drive him out and you can stay were you are and live happily ever after.