Hyundai Grand i 10 Car Work - My car not diliver after repair service

After accident last month ** october **** I gave my car to Sachin Hyundai Bareilly to service and repair. My car has zero depth insurance from AKC Hyundai Bareilly. It got repaired today ** october **** and I received a call I recieved from Sachin Hyundai to collect the car, I went there to pick it but they handed me a bill of INR **** out of nowhere I being a zero depth car insurance holder asked them to justify the charges and explain me why are they added. when I took the insurance I was asked to not pay any extra charges for any repair and services. No one from the service department gave me satisfactory response and have not handed me over the car yet. I tried reaching the customer care as well but it did not connect me to the concerned person.
Kindly look into the matter and help me resolve the issue ASAP.