Apartment leaks from top floor- not repairing

In which State are you?  Is it a co-operative housing society?  If not, have you got a registered or unregistered residents' association? How old is your building? Did the upper floor resident/owner carry out any plumbing or other work in his bath-room? How long is the leak?

Please do a civil report and then you can send legal notice to your neighbour and secretary (if any). Thereafter you can sue your neighbour and ask for compensation and mandatory injunction.

First you send a writing complaint to the concerned owner of the flat and copy to the association