Uber refuses to return my money after debiting my account incorrectly

On the 30th of July I used Uber to travel from King Shaka International Airport to Newlands in Durban, on a cash trip. I paid the driver, however Uber charged my credit card account in addition to the cash payment I made. It has been over 3 weeks and they refuse to refund my account despite proof that the trip was paid for. I have gotten numerous rude, flippant and nonchalant responses. I have never gotten such horrid service and will no longer be making use of Uber moving forward. I am shocked at their service!