If they phone you tell them you will have your own 'heavies' (you may want to use the word security) on site if they come calling. And by setting foot even on your drive or garden path they are trespassing and will be removed by force if they don't leave when asked. Then if they come calling again advise your 'heavies' to bung them into a car drive them somewhere quiet and give them a beating. Worked a treat for me.