Just give it back as bad as you get.
Lynyrd Skynyrd at 3am always worked for me. Or whenever they finally fucking sleep. I had to play with the times with my last batch of neighbors.
My favorite was blasting that and very loud sound effects, the most annoying ringtones I could find.
My worst was a recording of my cat yowling at full volume. That finally got them to come over and pound on my door.
There's something called Loctite...works wonders. I have a few bottles kicking around myself. Fill a keyhole with that shit and they'll never get it out.
IP Ticonderoga wouldn't run without that, brown heavy paper tape and pledge...no lie.
I've been dealing with shitty neighbors for years. I have lots of tricks. Lots and lots of them. Everything from mousetraps in bad places on a porch when I know they walk out there barefoot to putrefying kitty litter on a hot porch. Then there's the vaseline I left on the doorknob and the incense I used to burn.
A little backstory...
About 15 years ago or so, we (my family) bought half of a duplex in an economically depressed area, or an area that Sam likes to call "Little Harlem".
It was mostly old people and slumlords renting to mostly welfare recipients, who are the single worst tenants on the face of the earth.
The other half of the house has been purchased by various slumlords who do not check on their tenants and only own the place to collect rent checks from DSS.
We have single handedly made no less than 12 separate tenants move in the past 14 years because of noise and general assholeishness and this was only by forcing them to put up with a large taste of their own shit from us.
I know how to deal with shitty neighbors...believe me.
Oh, one more thing...keep the cops on speed dial. I had to for the last batch. They were making threats towards myself and my family at one point. Now the son of a bitch can't come back into the county because of noise complaints and general criminal behavior. He set up a rock band with amplifiers and everything else in the living room and tore out one of the supporting walls of the place in order to fit the shit in the house and played till 3am when I had to work. Cops came no less than twice and he was dragged in front of the local judge who told him it would be a good idea to leave town and not come back.
Worst part of the concert, he knew like two songs and neither were very good.