Cancelling an booked apartment before an agreement is made

Hi All, I have a question regarding the cancellation of apartment and refund of the money paid. We have decided to purchase an apartment in Bangalore. Here are the further details: 1. We paid 2L as booking amount through cheque. 2. The total cost of flat agreed while booking is 80L. 3. 20% of the amount will come to 16L in which 14L was paid in cash. 4. We have a receipt for 6L + 2L (2 receipts) apart from the booking amount receipt. Receipt for 8L was not given. Now due to some reasons, we are cancelling the booking. There were no terms and conditions mentioned in the receipts. We were given an agreement to sign and bring back but we have not yet given it to the builder. In the booking amount, we were agreed on the amount of 80L, but in agreement we have, it mentioned as 72L as we were not given the receipt for the 8L. 1. Is there a way we can get our money back? Because there was no terms and conditions on the booking receipt can we get 100% refund? 2. If the builder refuses to refund the 8L for which no receipt was given can we file a case using the booking receipt (80L) and agreement which was given for us to sign (72L) mentioned? Please help me with this? How can we proceed? I will talk to the builder first and then decide on how to proceed. Thanks in advance.