Nuisance neighbours

My neighbours living in Flat 34, Godrej Tower A6, Akashneem Garden Enclave, Vikhroli East, Mumbai 400079, are always noisy. They have this tendency to call out to their friends loudly after 10 p.m. in the night on the common lobby, play or sing loudly with all their doors open late at night, etc. We have complained to several authorities but to no avail. There is absolutely no need to be so loud and noisy when calling out to other people. They even hacked my computer and had several files stolen or deleted. They have gone way too far this time and are always opening their doors whenever we get parcels or letters to see where they come from, etc. They always have guests 24 hours a day. I do not care if that is the nature of their job but living in a residential society, they should understand the criminal nature of their behaviours but instead, they are gathering the whole building against me and my aged parents for no fault of mine. I am worried. I have never had such aggressive or lousy neighbours before.