Zoomcar — Change of car without intimation, unresponsive customer support!

I had booked a car, Renault Triber(7 Seater), on Zoomcar 3 days before my scheduled trip located 4 km from my location. They automatically made the car unavailable just before 1 hour of trip start. This is the second time they have done this in a span of 1 week. They did provide a link to select an alternate car. However they automatically assigned a Nissan Magnite(5 seater) that was placed 14km away from the location without any of my input. I did call Zoomcar support atleast 3 times without any response. I tried calling the support from different numbers as well yet no response. There was even no change in fare and there was no option to cancel my booking with refund. I forcefully had to go and accept the car against my wish as there was literally no response from their customer support. The car is of no real value to me as I needed a 7 seater but was forced to have an 5 seater. I want support on this on how to get this trip cancelled and want a complete refund.