I have an allotment letter of my flat from a builder since 2008 and the project was delayed and the OC is expected by Oct 24. I didn't register the flat as I never received the communication from the builder to register. I have now realised that the builder has sold my flat to another person and the registration is done between the other person and the builder. All my payments are complete as per the demand letter from the builder. What options do I have