false advertising

yesterday i bought a wireless keyboard and mouse. When i took it from the shelves, it price was R399 but when i got to the till to pay for it, it relieved a different price, which is R449. I told the cashier that this price is different from the one on the shelves. She then called someone to go ad check the price on the shelves, which she took longer on checking the price. When she eventually came back, she said she cant see any R399 on the shelves i pointed which i i took the keyboard from, so i went back with her so i can show it to her but when i got at the shelves, surprisingly there price tag R399 wasn't there anymore. The most frustrating part about this, is that even the price they say it is, it is not on the shelves. I can bet, the lady that went to check the price the first time might have removed the price tag. When i asked them why there isn't a price tag R449 on the shelves as the till says, they quickly dismiss me by asking if i am buying the keyboard or not.