Samiah International Builders — neither possession nor refunding my hard earned money

Address:

G-74, 1st Floor, Samiah Place, Sarita vihar Road, Shaheen BaghNew Delhi – 110025 (India), New Delhi, Delhi, 122002

We, along with my 3 family members, booked 4 (1bhk) flats in gulmohar phase -4 project in rudrapur samiah lake city in 2012 and made full payment of 4, 90000 each to builders on time. We have agreement and other payment receipt but builder is not constructing flat nor refunding my money. We all have been chasing from long time but no fruitful answers from them.
Every time sagir khan promises false commitment date, even no work will happen at site.

We are looking to file a legal case against them and required our full deposit money to be refund along with 10% interest charges.
Pls help.

Your's sincerely
Shilpi saxena
Saraswati vihar, gurgaon
[protected]