The price that you see is not the price at the till

On 02.01.18 I visited the new PNA The Sanctuary in The Whale Coast Mall to buy a original Lexmark Cartridge 100XL Black. The price of the cartridge was displayed on the shelf as R550.00. When I asked for the item the lady at the pay point took it from the shelf and again I ask her what the price is. She repeated the price as R550.00. Then she ask "do you want it"? Yes please I rep****. She then scan the price and it came up on the screen as R769.99 My response was that there must be a mistake as you just confirmed the price to be the same as on the shelf hanger R550.00 The pay point assistant then called the manager to clear the discrepancy and she asked her why the difference? She then rep**** to her and me "Sorry it was under the wrong price " Then the shocking question " do you still want it"? Buyers beware when you shop at PNA in the Whale Coast Mall as the price you see in not necessarily the price that you will pay!