Builder charging 10% cancellation charge on bokking

I had booked a flat in Pune 4 months ago..I had paid 6 lakhs to the builder. Now I want to cancel the flat due to some personal reasons, but the builder is charging a cancellation charge of Rs. 60 thousand ie, 10 % of the booking amount. we have not signed any agreement yet. Is there any change to get full refund from the builder.

Please suggest me since 60 thousand is also a very big amount to me which i will not be getting back.