Kulula going the extra mile to make my booking experience hell

NYNJIC - I purchased a return ticket for my wife and I for the comrades and had mistakenly booked our return leg a day too late. I then called Kulula and enquired on changing the return flight and Faranaaz (forgive the spelling) quoted me and asked for my credit card details which was on my office desk so I hung up and went to grab my card and called back immediately. I then hung on the line for Faranaaz for about 15min and a different lady answered stating that the price quoted earlier had changed from about R662 per ticket which I was happy to pay to R1280 per ticket which I then asked what changed since I was still getting economy flights and how could the price change that much in a few minutes? By the way the R1280 is after they subtracted the price I paid for the original tickets. They referred me to a supervisor who basically couldn't even answer me directly but had the call centre agent relay the message to tell me tough luck and shame in a different words. I cancelled my return ticket and bought new tickets RCID55 for the same time slot for cheaper than their ridiculous rip-off price quoted for an amended ticket. This is a proper rip-off because if they exchanged my tickets and only charged the differential then how come is cancelling your tickets and buying new ones cheaper? Customer service is atrocious and I cant believe how they couldn't find a way to assist other than to force me to buy new tickets which was cheaper than their useless offer to exchange at a higher price....unbelievable!!!!