Builder not responding regarding the property

We bought a flat in 2013 from Astha Gruh Nirmitte in Vasai east, Mumbai. We gave them the down payment and my EMI started immediately in GIC. Agreement mentioned possession in December 2014. However according to them, 2 builder fought and went separate. So my flat went in the other builders property while my agreement was with the other one. So they told us, that they will give us flat in another building. So we id registration and stamp duty for the other flat. Now they said, that we will do a loan transfer from the older to the newer flat. However till date they have not done any loan transfer, nor are they giving any possession. They have also closed they sole office, neither do they pick my phone calls ? Till now I am paying my EMI without fail. Please advice, what should we do now as we are worried a lot. It has been torture since 2013, the moment we took this property. Please also advice, can we get refund from this builder, as I don't think, he is going to complete the flat anytime.