I live in the garden flat, and the flat above are having a happy Friday very loud party.
My dh went up few times asking them to put the noise down as dcs are trying to sleep.
The fourth time he went up he was so angry and had a go at one of the guys.
After that they were making the noise louder and on purpose this time. 
I went at at 2am asking again nicely and explaining how the noise is horrible downstairs the guy who spoke to me pretended he just came home and promise he will tell them to stop.
When would u call the police at ur neighbor???