Most of the top builders always include a clause for compensation to be paid in case of delay in delivering the agreed services. They will have to pay you some amount of money every month for the delay. So, you should be very stern and more specifically ask about this clause while buying the apartment.
I guess it is the prevention that is better than the cure. Always buy apartments from a builder who provides the apartment’s occupant’s name. You should talk to them and get an idea about the builder. I have seen many builders advertising their homes by including the occupant’s picture with their contact details.
Confront the builder with all the documents you got from him while buying the apartment. Even if subsequent discussions with him turn futile, you should go to court and sue him.