The price on the item was wrong as per the manager

Thursday mid morning went for shopping at the Newton park store , when I went to look at the specials on the floor I saw a electrical wire in rolls and loose Marked R100, I took all what was of it to the teller but when I got the the teller refuse to scan , and call for the person in charge of electrical sale she just came with an attitude and dismissed us saying it can't be the price. After the argument we ask for the manager who also came dismiss us saying the can no way he is selling that at that price on it and he began to take the sticker off claimed maybe a customer did that , when I try to argue that's not my consent he even went and say yes the wires are on special but not on that price on the barcode, when i try to tell him maybe his staff is not doing their job he said the store is too big and busy for for his staff to worry about one item, for it sounds like an insult and undervalue me although I'm a paying customer