Lakdawala Developer Pvt Ltd review: Redevelopment building project which is stalled

Hi,
My maternal grand parents were staying in Kagalwala building, in peerkhan street, located at the end of the JJ flyover, Nagpada, Mumbai
Lakdwala builders got the project for redevelopment, they demolished the building in 2008, it has been 8 years but they are yet to start any work on the site.
They have even stopped paying the monthly rent.
Request you to please guide us as to where to complaint or what to do, as they need to shift every year due to the growing rents.
Despite having their own house they are now dependent on others and the builder just doesnt care