I am agree with Gangasagar. If it is a case of delay then you can file a case in the Consumer Redresal Forum and further obligated the developer to pay extra money as a compensation. A buyer was entitled to get his money back from the developer if he has lost interest in the property due to delay in its construction. But in your case, you will have to talk to the builder for the refund amount.
Have you registered your flat? If yes, then check the agreement. Is there any refund clause mentioned? If yes, then talk to builder about the refund. But it is very difficult to get your money back from the builders instantly.