Know Modus Operandi of Ravi Group to cheat; know how to safeguard you!

Recently we had bought a flat from Ravi Developers in mira road. Name of the project is Gaurav Woods. There was no possession date mentioned in the agreement and it was committed by the builder that with 6 months after the agreement done the possession of the flat will be given to us.Till date we have just got temporary possession and also no lift and water supply has been given to us. We are on the 9th floor and it is becoming day by day difficult to manage up till 9th floor everyday. Please suggest what should be done teach a lesson to such an errant builder.Thanks for your valuable information.