UBER - Uber overcharged me and refusing refund

I had booked Uber cab for my relative from Ejipura Bangalore to Shankar Mutt Road, Shankarpuram, Bangalore on **nd June @**:** PM. The uber cab number is KA ** AF **** and driver name is Puneeth Kumar.
The ride was to be paid through Paytm wallet. At the end of the ride, the driver asked my relative to pay cash for the ride.
My relative said the ride is already paid through Paytm. However, cab driver disputed that ride was cash ride and not linked to wallet.
I called my relative at the same time and talked to cab driver, asked him to give me screenshot of the app showing to collect cash Rs ***/, he refused to give me the screenshot, asked me to contact customer care and demanded the money. My relative had to give him the cash.
I contacted the customer care, they plainly refused to refund the money saying the transaction was done outside the uber system and they have no control over the same. I asked them the driver phone number, they refused citing privacy policy. I asked them make conference call, they refused to the same citing privacy policy. They were unwilling to confirm the details from the driver.