False Prices Displayed and Rude Supervisor's.

I went to Waterfall Spar this morning and saw a card at the milk section which read "Spar Full Cream Milk, 2L - R19.99" so I picked one up with the exact same description but the till wanted to charge R27.99. I bought back the display card and the supervisor and manageress were called over - they both said, that's the price and walked off with no explanation or apology! This rude behavior is unacceptable and would never have happened under the previous ownership.