Applicability of stamp duty in case of cancelation to purchase property

Respected sir/madam, I am from Vadodara, Gujarat. I planned to purchase a commercial property I.e. Shop and I paid 25% amount to concerned builder against the purchase. We entered into agreement and registered the "Banakhat" with local body. Afterwards we asked builder for documents for purpose of loan and he provided a set of documents. We submitted the application for loan with documents given by builder. Lawyer from bank raised query regarding insufficient documents mainly non availability of N. A. For commercial purpose, unavailable title clearance, unavailable entries in form 6. With the said requirements we approached builder but after 3 months also no documents are provided. Hence to avoid any legal consequences we planned to cancel the deel. We approached the builder and informed to cancel the purchase deed. Now he is asking us to pay 1 % of total consideration as stamp duty to cancel the deed. He is also denying to repay the amount in time stipulated by RERA act I. E. In 30 days. My two main questions are. 1) is any stamp duty payable by purchaser of commercial property in case the deed to purchase is cancelled? If yes to what extent.. 2) if builder denied to follow RERA rules and provisions what legal rights we have as consumer against builder.