Refuse to take responsibility for wrong pricing

I went to Engen hazyview around 19:30 . Date 16-04-16. As usual to buy my daughter her favourite mini-eet sum-more biscuits. On the shalve was the usual R5.50 price. Abigail hhe cashier scanned R7. And insisted i pay it as it will be \deducted in her salary\". She mentioned that Hennie the manager was responsible for that and he was unavailable. Insane. I need explanation and apology from Abigail and the manager Hennie."