Bad customer service

I would like to lodge a complain for the customer service I got from sports scene forest hill. I wanted to buy Red puma foam for R799 I saw the price at the other shoe at display when I go to the terminal the cashier said is R899 and they said is mistake and they can't give me with that price because he is gonna under bank. I said to him the price I see is the one i have to pay he said to me m gonna give you your cash back and you gonna buy it at other stores because he CANT sell it with that price. I have a proof for that sneaker and he said I can take a picturefor that because he DON'T Care. Worst part he is the store manager.