Dishonouring quoted price

This afternoon at about 15:00 my daughter wanted to purchase two bar stools. The salesperson gave her a quote of R799 for one bar stool. She indicated that she will purchase two stools. However, when she came to the till she was told that the stools were R999 each. She came to me and explained the situation. I asked the person who seemed to be the manager, Se**** why is the price suddenly R999. When the salesperson gave the quotes he could distinguish quite clearly between tools costing R499 and those costing R799. Se**** started giving all kinds of excuses and said that it was an honest mistake. I asked him why is he not honouring their quote and he repeated that it was an honest mistake. This is unacceptable behaviour and here Se**** could easily blame his salesperson and think that he can get away with this kind of behaviour.