Pricing and Bad attitude

Today at 16:00 my daughter wanted to buy a nougat lolly priced at R4.90. The cashier scanned it as more than R15.00. She refused to give it to me for the shelve price. She adamantly put the item aside and said she can't give it to me for R4.90 although I showed her the box with lollies marked at R4.90 each. What happened to respecting the display price? I am very disappointed in Sweets from Heaven Umhlanga Sands. Won't support them anymore.