Ola Cab Gurgaon - Ola driver has taken money for a post paid ride

I am not familiar with Ola , oneday I forcefully had to use ola, I download the app and used it for booking from Gurgram to Alakananda. The APP itself has taken postpaid option, I was not even aware of such option. When the driver dropped me I asked him for the bill he said, there is some technical issue and cant take the bill. The amount might be in-between *** to ***.So I paid him ***. I noticed it when I opened the email, it says your payment is pending. I called customer care, they said its already * days over we cant talk to the driver. They are not even ready to ask the driver for the incident. And asking me to pay for the ride again