Fishaways refused to give me a refund

Good evening today I went to Fishaways Galleria, Amanzimtoti. I ordered F1 hake small f chips and S 5 pop prawn fr 5. I was not happy with the prawns then I've asked them to cancel my order and replace it with hake and chips. The store manager Melusi refused to cancel my order he said there is no other option I'll have to take what I've ordered cause I'm the one who asked for it. He also said I ordered these grilled prawns cause I know them now why am I cancelling there'll shortage of stock. Since they were pushing me to take these prawns I ended up saying they can keep the money and prawns cause Melusi told me that there is no other option and even asked what are they going to do with these prawns. I strongly believe that my right as a customer were violeted because I ended up paying for nothing since they also refused to give me a refund. According to the consumer`s act I have a right to cancel of I am not happy with the product. I also feel that Melusi does not have good customer service because when one of the cashier's called he regarding this matter he said "what must i do?" The cashier responded by saying that he need to take action as a manager but Malusi responded by saying that she's a cashier too so she must find a way forward too.