No Adhering to the Consumer Act

I went to Truworths store in Sandton City on 08/11/2017. On display I saw a dress and below it was the price. Now when I went to pay for it, the same dress scanned at a higher price. I informed the cashier that I saw a lesser amount on display and I would like to purchase the dress at that price. The cashier then informed the manager and store manager of my request,however both of them told me i couldn't get the dress with the price i saw on display. I was told it was an error on their side and they acknowledge the error, however I cannot get the item at the lower price.

The store manager took my contact details and PROMISED that either she or the Regional manager would contact me. I haven't received any call from either. I suppose i don't matter...

Now I know that the consumer act states that if there's two prices for the item, the store IS NOT ALLOWED to charge me the higher price, see below sentence:" Consumers have the right to demand paying the lower price for goods displaying two varying prices – suppliers are not permitted to charge consumers the higher price for the same goods."

SO WHY IS TRUWORTHS SANDTON CITY CHARGING ME THE HIGHER AMOUNT?