Interest charged by builder

Good day, I booked a builder floor in 2013, and paid 20 percent of the TSC, and planned to subsequently take a home loan from HDFC bank. When I approached the bank they informed that the unit is approved for disbursing. The builder kept on saying that they are in discussions with the bank to get the approval and on email kept saying No interest will be charged till the bank disburse. In 2016, I received a letter of intimation that the apartment is ready and demanded all the principal along with a humongous interest. The status of approval still is that HDFC has not approved the loan as yet. The builder started mentioning that the BBA does mention that the customer has to pay irrespective of the bank approval or loan. I managed to self finance the project and have paid all the principal, but the builder does not send me a SOA without interest and I belive his intentions are try and maintain that I have pay interest. Can I take recourse on numerous email I have from the builder to ask him to waive the interest as per the emails. Best regards Sri