Zoom Car India Pvt Ltd - Not refunding back the money

I made a car rental booking on ** Jan **** through Zoomcar mobile app.My zoomcar booking id was JPS*NN*EJ. The car was booked and the money was deducted from my bank account. But, the car was unavailable for the required booking time. This was the problem with zoomcar as the booking should not have been approved if the car is not available for the required time slot. Still, my money got deducted. The amount was Rs **** ( refundable security money: Rs **** and Booking charges :Rs ****). Since, that was the mistake from their side, so my claim was subjected to full refund as per the refund policy of Zoomcar. I talked to a customer care executive and he promised me that the refund will be paid within ** working days.Now, my money is stuck with them. It's been more than ** working days since then and the refund amount has not been paid to me yet. I can't even talk to customer support executive on helpline number now as they allow only the mobile number with ongoing booking to connect.