Shobha Limited - Builder Deducted Money from my booking amount

I booked a flat in Shobha Townpark on ** August, **** and paid a ** lakh as the booking amount through various modes.
Later my plan changed (as I was looking for bigger apartment and need time to decide) and requested to cancel the booking on **th August (this is within the ** days period policy to refund without any cancellation charges) and refund my money.

Builder said you are not sure take time to decide till **th September. Then are also if you want to cancel then there will not be any cancellation charges. THis they given me in written in email.

I put the cancellation request on **th September. After this they took approx. ** days to refund money. They also deducted **k without giving any explanation.