Damage to intercom and wall paint

Every month my front fence gets decorated with CK Gate and Automation advertising stickers. It damages the paint, and now they started cmsticking it on the intercom, over the speaker area, so only when I check why my guests cannot hear me, do I see that they stuck their advertising stickers over the speaker. When I call them and asked them politely not to do this, the owner yelled and cursed at me and said he has the legal right to. Since when can you use other people's perimeter walls as ad space?