Flat on the floor above - Encroaching the Pipe area

Hi All - I have a flat on the 6 floor of Purva Sunshine Apartment on Sarjapura Road Bangalore. It is a old society more than 15 years old. The builder is completely out of the picture. The area where there are pipes coming out of the bathroom is open. It is built like a shaft or a duct (covered from 3 sides by walls and open on one side). The flat above mine 7th one is the top most flat and they have covered the area from the top using Iron bars and built a platform for themselves. It is like a small extra balcony for which they have not paid anything. This is completely illegal. The EC of the society disconnected their electricity but the owner got the BESCOM engineer to call up society and instructed to connect the electricity back. The EC now is not showing interest in resolving this situation as they have not been able to do anything. As a result of the platform, There a lot of birds which have gathered below the illegal construction and in front of my bathroom window. It has become a huge mess with smell. Plus the owner of the floor above can directly peak into my bathroom. And we have to keep the window closed. Questions: 1. Which authority can I approach to get this illegal construction removed ? 2. Which authority is responsible for ensuring that the flats do not encroach on the areas which are important from the perspective of fire safety ? 3. I have seen some flats stopped paying maintenance fees when they faced issues with other flats and those were not resolved for long time. Shall I also stop paying maintenance fees ? What are the implications for me ? 4. How can the EC be made to act on this issue ? 5. Shall I also get some construction done similar to the flat above to clear the mess and get an extended bathroom ? 6. What are my legal options ?