Disappointed and want a refund

I brought my son a pair of havaianas at V&A Waterfront in September 2020. On the 28 November 2020 I took the slippers back to the store because it was broken. The sales assistant refused to refund or exchange the slippers because according to them it's a wear and tear problem and they can't do anything about that . But the one slipper broke by the toe side and I can't fix it . So now I'm sitting with broken slippers which I paid R320 cash and still have the purchase slip. I'm really disappointed in the quality and service that I've received of an international brand.