Sportscene selling defects

I recently returned a shoe at Mall of Africa because it had a defect, your staff at the store knows about it but I see it's currently on the shelf for sale again. Why are you selling a defective shoe to consumers?

I asked the staff at the shop why are they doing that, told me that they it's non of their business and nothing they can do about it because the shoe shows in on their stock. As we speak, the shoe is on the shelve selling at the exact same price I bought it for R2139