Bad attitude and pricing issue

I just went to the Kwik-Spar in Die Neelsie in Stellenbosch. I was charged the normal price for a box of cereal instead of the discount or \special price"advertised very clearly in the store. After notifying the cashier that she had overcharged me she gave me my money from the cash register. My issue was her dismissive attitude. She removed the cereal box from my plastic but did not repack it. I received no apology. Instead of saying sorry she moans to her cashier colleagues about me being petty. There is a huge difference between R33.95 and R25.95. I am not happy with the service. As a customer I want to be acknowledged and have a decent level of service to be delivered and not for people to dish out an attitude."""