Brigade Group — Interest Charged to the customer too high and rude Customer Service

I am one of the customers who purchased a flat in Kino, at Brigade Orchads, Bangalore recently. I had written emails for interest waiver, i have paid a sum of around 4.5 lakhs to brigade for the flat booking. I know the apartment is currently in the building stage and the handover is supposed to be Dec 2023. I had requested for a two months time to apply for a home loan due to some complications in my new job. Surprisingly the amount that i made to an amount of 2.5 lakhs is missing in the interest calculation and i am really not sure how is the interest amounts to 55 thousand for 4 months, where in my booking was done in March and i already paid an amount of 4.5 Lakhs and i am said things like "i might have to forfeit the amount paid if the payments are delayed. I have to attend to only the calls i received and i get to hear rude behaviour of your executives and i cannot reach on the customer care number and have to reach them only over email and the ticket gets closed without a proper closure and a one sided answer with no customer support
Just that I had booked the flat and the business is done. So does brigade thinks that an existing customer will not be a client in other projects. The dont want to get into the sales part and how I was pushed into buying the flat.
Request you to kindly check on this and provide a solution for this.