Refused a refund for a faulty microwave

My mom bought a Defy Mricrowave from Fairprice Wynberg on the 22nd February 2020. The microwave is faulty, when she warms food it smokes and smells of rubber, just 3 days being bought.

She went to the shop tryig to get a refund so she can buy a new microwave. The Wynburg branch refuses to give her, her refund. But they took the appliance and forcing her that the microwave gets repaired.

Kindly resolve matter so she can be refunded. (She doesn't want a used repaired appliance, hence she went n bought a new one!) The managers name is Nokuthula, who she and the staff where rude to my mom in the shop.