I rented a townhouse at the beach in La Jolla 10 years back and was at my wits end over some loud 24/7 party animals that rented across the street… I’m talking all night and still going at it when I left for work in the morning.
One of the neighbors got the landlords home phone number and passed it out. I called it in the middle of the night and told the landlord I wanted them to have a shitty nights sleep like the rest of the neighborhood. They stopped picking up after a couple of nights, but the renters were gone in less than 30 days.
Might be a good strategy to get the landlord to put some soundproofing in the floor.