Bad attitude

On Sunday the 7th of January 2018 I went to Spar at phola mall, I wanted maize meal that costs R50 manager's special, I mistakenly took the one that costs R44 for 2 an if you buy one the price is R30. When the cashier gave me change( R20 and some cents) I was surprised, then I asked her how much is maize meal because I want the one that costs R50, instead of telling me the right thing, she told me it is not her duty and with bad attitude. I wondered what her duties, since she repeatedly told me it is not her duty. That type of customer service displayed by Punky Mtshweni is going to drive us back to other shops because of one person.