Vastu Vihar — Work started without any intimation

I have booked a JAYANTI BANGLOW in Aurangabad, Bihar. I have to make many modifications and extra works. But, project Manager has started the work of plinth level.
I had requested him to start the work of my building after a Bhumi - pujan by my family members. He had assured too. But, informed me after piling Completed. Now, giving a pressure for payment.
So, I'm looking for Cancellation of the Booking.