Possesion of the flat..!!

Hello Sir, My name is Aman Makani, i Stay in Hyderabad. My Dad booked a flat on his in a project that was being constructed by Anshu Constructions and which started in 2007 we booked i n 2008 and the possession was to be allotted by May 2012 but in between the project was sold to Beccun Construction and we had a new agreement accroding to which the possession was to be alloted by 2014, but yet the project has only 3 slabs that has been layed by the Anshu constructions, there is no new work done by Beccun Constructions sincce the project was handed over to them..! the contract states that if by 2014 the possession is not been granted the builder is liable to pay a amount of RS 7000 INR as the rent towards the flat but we are not receiveng any amount from the builder and he never meets us as well. and now we have come to know that he has sold the project to some other builder and has declared himself as Bankcorupt in the court of law but he has a lot of projects running and as well as hotels too. he is not also ready to talk to us or neither to repay the amount that we have payed him, we have also sent him a legal notice but he answered saying that you people have waited for so long wait for next 2 months we will take out some solution but its already 2 months now but there is no proper response from him yet, please advice us what shall we do. we are a total of 50 flat holders of one building from the four buildings those were proposed in the project. we all are willing to get our money back now as its been a span of 8 years that there is no single construction of the projet yet.