Case against builder collectively in NCDRC, total value exceeds Rs 1Cr

We are group of around 10 people who have booked flats in a project of a reputed builder in 2013 with promise of delivery of flats after 36 months. Cost of each flat was around 20 lakhs, and each one of us paid around 7 to 8 lakhs as initial money. However, despite full project being sold out, builder did not started the construction and by 2016 cancelled the project. When approached, though builder has promised to refund the entire amount with interest but so far have failed to deliver. We want to file a case against this builder in consumer court. We have two queries: 1. Can we file the case directly in NCDRC court as the total value of flats exceeds rupees 1 crore and secondly 2. Should we complaint through a registered association or file the case through a representative complaints on behalf of all buyers. It would be great if you can answer our queries and also hint about the professional fees. Thanks and with regards