I had the worst experience with an ubereats driver who I paid cash for a delivery and he said I did not pay and Ubereats wanted me to pay double for the order

I had the worst experience with an ubereats driver who I paid cash for a delivery and he said I did not pay and Ubereats wanted me to pay double for the order. I sent a message to them and they said I owe and have to pay. How can a driver deliver without receiving payment when it's a cash payment?