CC, OC and Association/Society formation

The Apartment status and scenario is as below: 1. Construction in all respect should have been completed in Jun2016 at max. 2. Basic necessity and amenities pending e.g. Permanent water lines, Elevator, Compound Wall, Electricity power backup generator, Swimming pool, Gym, Club house, security. 3. OC and CC not yet issued. 4. 7-8 flat occupied out of 32 flats. Most of the 32 flats are registered. 5. all residents have gone through lot of mental torture and are helpless. 6. Sent builder notice, by individual flat owners individually. More than 3 months past, no response from builder on any of the notices. 7. Apartment location is in Bangalore, near Bommasandra. I have the below question: ---------------------------------- 1. Can the 7-8 residents form a association/society? Is builder insolvent required? 2. Should we file complain as Consumer court or Civil or both? 3. I believe is better to approach legal system as group instead of individual parties/flat owners, pls guide/suggest. Thanking you Avishek Kumar