When is the customer right, what does the Consumer Protection Act

So I enter the store looking for a bathroom scale. I ask one of the store workers to help me find one and when we do we see a scale priced R99, when the lady checks the price at the till it reads R499, but we all clearly saw it priced at R99. I ask for the manager and a lady called Goodness comes who argues it is R499, who then calls a senior manager Ntombi who says the cannot and will never give a customer something that was clearly a mistake on their part. I have picture evidence of this. I'm quite perplexed by this situation.