Godrej Properties — Charging Interest after they delayed everything

Hi I booked my property at Godrej Icon in Sector 88A in Gurgaon on 9th of June 2021. They said to pay full amount in 45 Days with 10% payment to be done in 18 days from booking. After a week I was constantly checking with them to confirm my booking and finish the BBA so that I can apply for Loan. But their CRM team sent me a booking confirmation on 28th of June (18 Days after booking a property). I made a payment of 10% on 2nd July and asked them to quickly do the BBA as I don't have time and loan process will be delayed further. Finally, they did BBA on 7th July. Then I constantly started requesting for agreement as Banks require it. They said I can collect BBA on 19th July (25th was end date for payment). Due to very Bad weather in Gurgaon I said please hand over BBA to bank. On 23rd of July they handed the BBA to Bank. Finally Loan got sanctioned by 4th of August and full payment was made to them. But Now they are saying I also need to pay the interest amount too.