Bad attitude

I just got out of dischem northgate with anger i was buying my baby purity cereal which on the shelf its r19,95 bt whn they ring it the price was r23,95 i told the cashier tht i saw it for r19,95 she went to check the price apparently they wr 2 prices so the cashier told the supervisor she said she wont authorise it cz its r23,95 y do i want it for r19,95 the attitude she gave me was unacceptable she told m tht she wont gv it to m for r19,95. My point s it wasnt my problem as a customer tht they ddnt do price change in the morning....