Neighbor put up their own No Parking sign on an area that is free public parking for their Airbnb guests

Hey, I live on a street with free public parking and my neighbor across the street runs multiple Airbnbs from their home and recently put up a No Parking sign with threat of towing on a section of street that is for free public parking. Anytime she sees a car parked there, she leaves baseless threatening notes on their car. Who can I report this to? I tried reporting it to LPT but they never responded and was wondering if there’s someone else I can. Hvala.