Bad Customer Service

Yesterday I popped into pick n pay Senaene to quickly buy myself some roll-on, walking into the aisle comparing price top rack packed full of Adidas roll on with 2 signage pointing to in bold R14,99. As I got to the till it scanned R21,99 a supervisor was called who then said to me she would not give it to me at the price advertised on the aisle and that it was my duty to carefully read the barcodes and that it must have been a customer who placed the roll-on on the wrong signage but then when I questioned her as to how can a customer remove a whole bunch of roll-ons and place them right at the top at that specific spot?? that customer must have been bored at home and just decided to go and rearrange pick n pays shelves. Then she said she would call the store manager for me and along came a lady by the name of Karabo who then pretended to be the store manager who then told me that it's not their fault not problem that the items were had the wrong price . She further more insisted that she WOULDN'T give it to me at the price advertised? what ever happened to CPA, have I no right to pay the price I see??????