construction not started even after two year

Hi,
I have booked one flat in Ekdant group project ‘Ekdant rawal residency’ in sep-2012 and even after two year the construction work not started and they are not giving actual picture, they are giving next schedule date for commencement of construction again and again.
I had given the Rs. 5 LACs as a 20% payment of flat as an advance and my money has been stuck for last two year and that is why I am unable to book flat any where els. When I am asking them to refund money with interest then they are not ready for the same, very often they are not responding properly.

Request you to please intervene and available me with my refund money with interest or they should start construction after getting all approval as per Govt. norms so that we may avail home loan and I can get my flats.

Please help me out.

Regards
Noor Alam
mobile no.-9971331890