Setback Violation by the Builder

Hi All, 

I request your suggestion / help with the issue I am currently dealing with regarding setback violation by the builder. 

I have a 60`x40` plot where I am planning to construct my house in Bangalore. Next to my plot, a builder (GPA) and along with the site owner are constructing a G + 3 residential complex maybe like an apartment on a 60X40 plot. They have just laid out a first slab which is just 6 inches from the boundary of my plot. I have requested several times to the builder as well as the owner of the plot not to violate the setbacks, but they are not ready to modify the building plan and the builder seems to threaten us. 

So, I have lodged a complaint at the BBMP Ward office about it and they have acknowledged and promised to take action. 

My request to you all is to let me know what should be the next plan of action? Also, I am not aware of the re-percussions. Kindly suggest/ guide me.