Billed twice for one trip

On Wednesday the 7th February 2018 I took a taxi from work to home. I had put cash option bcos my card had no funds, to my surprise when I got home the card rejected and said no funds and so paid the driver R50 cash for the ride. I informed Taxify about this and said their system had a problem and could not switdh options on the APP but they billed my card anyway a few days later. Today when I aksed for my refund they(Laura) say the driver(Nkosiyethu) denies I paid him cash, and when I called the driver he says they haven't called him to verify if I paid cash. They are ******** and are robbing people of their hard earned cash!