Saa day light ******* and ****

I booked a return flight and missed the going flight.. Made a plan to fly to Durban now I want to use my fly back ticket and they telling me I have to pay R2000. How can I can for sumthing I already bought. I paid for the flights and if I miss a flight it's Mt loss not them why should I pay again for my return flight which I already paid for... Flight SAA is a ****... Daylight *******.. I paid R1800 for return flight since I missed. Y going flight I must pay another R2300. What law is that. 😡👹😡👹