Being constantly bullied

I live in a flat, my nightmare of a neighbour who lives on the opposite side of the building and floor below me who I haven’t met or seen since the incident I am about to mention decided to smear turd over my front door and carpet in the communal hallway. I am the last flat on the the top floor and still have no clue why he did it. I have been told he is mentally ill. I really hope it wasn’t his own he smeared over my door. But he has been purposely buzzing the intercom system to my flat, breaking into my mail box, stealing my parcels and calling the housing authority on me with some really absurd claims. Luckily my neighbour below vouched for me despite only seeing them rarely in the communal hallway. 

I live in a flat, my nightmare of a neighbour who lives on the opposite side of the building and floor below me who I haven’t met or seen since the incident I am about to mention decided to smear turd over my front door and carpet in the communal hallway. I am the last flat on the the top floor and still have no clue why he did it. I have been told he is mentally ill. I really hope it wasn’t his own he smeared over my door. But he has been purposely buzzing the intercom system to my flat, breaking into my mail box, stealing my parcels and calling the housing authority on me with some really absurd claims. Luckily my neighbour below vouched for me despite only seeing them rarely in the communal hallway.