Here's what you do. Dig the sidewalk down 50 feet. Just a sudden drop. 200 foot tall fence made of barbed wire and spiked metal. This reaches all the way to the 50 foot drop of the sidewalk.
The sidewalk is public property. So if he throws it down there, it's littering.
The fence is also electrified. Your mailbox is on the front porch. Thete's also random landmines in the yard, and swinging chainsaws being whirled around by pulleys.
Lets see him deliver those weekly savers ads now!