Refund required for unnecessary overcharge on my trip

On Monday morning 11 June 2018 I took a taxify from Florida road in Durban to King Shaka airport. The driver arrived and we requested him to drive a bit faster as we were running late, he advised that he cannot drive more than 100km/h as he was saving on petrol. He also decided to take the longer route to the airport. He dropped us off but did not not end the trip. When I landed an email with the receipt for the trip was received and it was double the amount which was supposed to be charged for my trip. I then tried to call the driver, he did not pick up. I sent him a SMS requesting an explanation as the drop off point and drop off time on the invoice were not a reflection of the truth. There was no response from the driver, I then sent multiple emails to taxify requesting that the they refund half of the money they took back into my account. The feedback I received was offering me a promo code for a next trip. I rep**** back and requested that I do not want a promo code but I want my money to be refunded back. There has been no response from anyone at Taxify regarding my request. This is frustrating as it seems like the driver did this on purpose, he did not even have the decency to apologize or let me know of the error. This is not a first incident with Taxify drivers not ending trips on time when they see that the selected payment choice is a card.