Consumer Redressal

I own an apartment on 1st floor of a 3-storey building in Chennai. Immediately after 6-months of possession, I noticed leakage in the roof of my bathroom, which I brought to the notice of the builder. He did some repairs in the 2nd floor bathroom. But again after 6-8mths, the leakage was seen. When I approached the builder, he first refused to help, later agreed. But the tenants in the 2nd floor apartment refused to cooperate and did not allow any work being carried at their place. I spoke to the owner who stays in a different city. He plainly refused to cooperate. He argued that he could not allow discomfort to his tenants by allowing work in the apartment. I approached the building association formally and informally, but there was no support from that end too. I am told that it is my personal problem. It is 7-yrs since we are suffering with dampness and molds with paint peeling out from a large part of my flat. There are ants inside the wall. Pls suggest how can I solve.