Dispute of Consumer pricing law

I went to pick n pay Bredasdorp and bought Johnson & Johnson wet wipes, when I got at the till the wipes were scanning R39.00 then the cashier went to the till to Check the pricing and she saw the exact pricing which was R35.99. I told them I need to pay the amount I saw they refused called the supervisor and the guy who claimed to be a manager his name was Chris, I told him about the consumer pricing law and he told me they are not pick n pay and that law does apply to them.

What kind of a service do they provide and since when does a consumer pricing law don't apply at Pick n pay?

I'm thinking to my self which other laws do they ignore? Are they above the law? They even sell old food and they are sarcastic to their customers. I am beyond disgusted with the service they provide.