1. File a complaint case before the local District Consumer Dispute Redressal Forum alleging deficiency in service and unfair business practice claiming direction upon the builder to complete the work within next 3 months or pay penalty at appropriate rate, pay rent for staying in similar type of flat in the same area from the 10th moth till possession is handedover to you, damage and cost,
2. If all the persons who booked flats in that building file joint petition, your cost will be comparitively less for filing and persuing the case,
3. Consumer court is faster than other civil courts.