Builder is objecting to change the property as per drawing

Hi, I have bought a Villa 3 year before from a builder in Bangalore which is now at a final stage. There were few mistakes/faults in the construction (construction not made as per final drawing). Initially when I requested for change or compensate, Builder has agreed to compensate. Recently, I have requested builder to correct one of the faults (shifting of window as per drawing) so that I can release the payment. He's neither confirming to shift the window nor responding on compensating. In fact he's forcing me to go for registration without completion of Villa. Also threatening to cancel the Villa if I do not release the payment. 80% of payment is completed. He has raised the demand for 10% payment (last 10% installment has to be paid during registration). What is the solution for me if he tries to cancel my Villa on the basis of holding the payment. I have asked him only to confirm to the modification to release the payment. I have already invested around 6 lakhs for additional interior work in the Villa. As on date Builder has delayed to deliver the Villa for almost 14 months. What should be the best option for me if he goes on for cancellation. Thanks, Mahesha P.S.