Yes, first of all make a Whatsapp or Face Book Group and ask all the buyers of this project to join. Once they joined then call for a meeting. Take the decision and file a suit in the civil and criminal court and ask for the compensation.
Yes, file a consumer complaint in Group. If you make a complain in a group for the same project then it will impact a lot in ur case and it becomes easy for the judge to release the case as soon as possible as it related to a group of people. Group cases are frequently handle by the court compared to individual case.