Refund of token amount given for Booking of Flat

Hi Booked two flats (1BHK) in Lodha Amara thane. Paid the booking amount of 1.08 and 0.5 lacs for respective flats on 8th Feb 2020. Also provided cheque of ~3 lacs for each flat as next payment. The flats are at ground floor having carpet area 454 sq ft with attached balcony of 150 Sq ft. While discussing the flat sales person never mentioned about that the balcony will not be part of registered agreement. I got to know it only after paying the token amount. After that I told them to include it in registered agreement as based on that i have negotiated the price. Builder refused to do that. I told them than I would like to cancel the booking. They are saying, there is no cancellation policy so the booking amount will not be refunded. Please guide me what should be next step. I have stopped the payment of the cheque given to them (of 3 lacs each). Is that sufficient or I will be in trouble because I have given the cheque dated 8th Feb.