Sobha Developers - Overcharging of interest

Hi,
I have booked a flat in Sobha developers at Sobha Dream acres project since **** I was asking to understand the status of the apartment. There is no proper response from the developers, they used to communicate only through email (The email contains only the payment to be done). I sent several emails and now the apartment is ready for possession, I stopped paying the EMI since they have not shown the status of the apartment and I had doubt about how they are constructing the apartment. I have several doubts like how the construction went since they intentionally not allowed for apartment visit during construction. Now there is an accrued interest of Rs. *,******. If they are not providing proper status why will I need to pay the interest amount? I informed them that I am ready to pay the principal leftover. Total I paid ** Lakhs and in the remaining ** lakhs, they are asking to pay **.* lakhs(*.* lakhs additional). My apartment id is A*-*****. What should I do now?