Supertech — delayed completion in supertech golf village yamuna exp

I booked a flat in 2013 with supertech but till now there is no sign of completion.in fact when i visited the site few days back i found that the construction work is completely stopped and there is no one to hear the grievances. I am really not sure what to do next. Where can i complain and how can i get my flat.

Not sure if there is any forum or group of people suffering because of same builder.