Cancellation of flights VNPDFT

Good day.

Last night i booked flights online at Kulula.com. After paying for the flights I immediately realized that the dates were incorrect. I logged back on and tried to change the flight details. I was told to contact the call centre. When i called the call centre it said they were not available. This morning i called the call centre and explained the whole story. They told me i could not cancel the tickets but i could change the dates for an "extra fee". I said that's fine. They then calculated the "extra fee". This amounted to R 2023.00 per person which meant i had to pay in an extra R8000.00. This is absolutely ridiculous. These are for flights from Johannesburg to Cape Town, not even abroad. The initial price for the flights was R 7900.00. Now i would pay double the price because of the "extra fee" of R8000.00. I asked them if i could cancel and pay a penalty fee perhaps. They said no, the tickets are non refundable. This is totally unacceptable. They are not even willing to meet their customers half way. I am really disgusted by the lack of customer service.