Charge you 4x the price to change tickets

Tried to get an earlier flight to Cape Town with SAA, already booked with them and the website says R342 to change your dates. Was informed to change my seats would cost R10k for four people, R4k more than I paid for my entire journey. Booked at R6k and they want another R10k to change my flights. No wonder people don't want to fly you, your business model stinks! Will never book SAA again.