Repairing work - Issue with neighbour

Need Legal remedy for Continual suffering/harressment I bring to your attention the routine leakage, seepage from the flat above my flat for more than 2 years. The false ceiling is corroded, broken and hanging. The iron support (tor steel) to the toilet seat is heavily corroded. The owner does not respond and doesn't repair it. The flat owner maintains that he is not using is and doesn't seems to be interested in repairing it. The complaint is registered several times to the society by mentioning in the complaint register. The response from the owner is that we are not using toilet. there are photographs showing damages and leakages. The condition is pethatic. I don't know the intensity of action of our RWA on the concerned flat owner. This is a case of intentional harassment and the family may get seriously injured and may die as well due to falling of Tor Steel and False Ceiling. Need to know the legal remedy and the role of RWA and the Association of RWAs of the Group Societes.