REQUESTING UBER TO PAY BACK

I requested a ride with a ubber the driver accepted and I paid with my card automatically then the driver on his way he texted me to change it to cash which I responded I don't have cash and I was already charged, he arrived and he canceled the trip and left sighting he does not have petrol, worse ubber did not returned my money mind you that all I had I waited for hours it was raining and I was cold waiting for ubber to return my money so I can request another ride, I had to make a plan which came hours later, I wrote too ubber on their app with no success. Kindly assist