Atrocious returns policy and flouting of the law (CPA)

I purchased 8 items on Black Friday for over R2,500. All of the items were marked FINAL SALE because it was Black Friday. Three of the items are too big and I wished to exchange them for smaller sizes (which the company has stock of). The company is strictly an online platform and service and, therefore, there is a strong likelihood that the clothes will not always fit. It is unthinkable and illogical for the company to have an atrocious and prejudicial returns policy, BUT THEY DO! However, the company simply and obstinately REFUSES to simply exchange the items, due to the fact that they marked the items FINAL SALE. Their conduct is ******* as it is in direct contravention of the Consumer Protection Act. I have advised them of this but they simply don't care and will not change their minds. Their conduct is reprehensible and unfortunate and I will NEVER buy from them again. Shocking and deplorable service.