False advertising and bad customer care

I went to buy a Cot bed at Jet and saw one Chellino camp cot at Jet greenstone advertised to be in special from R699 to R599. I then requested for it and was told there were only left with the one in display and I could purchase it for the price displayed, that is R599. I then requested for it to be packed so that I could purchase it. On arrival at the pay point I was told that the cot was no longer in special and I should pay the regular price. I asked the till operator to call the manager who came. The manager had a very bad attitude and told me that the display was supposed to have been removed by one of the staff members the day before but was not. I then asked her what she was going to do about that since as a customer I had been prejudiced through false advertising. She responded that she did not know and could not do anything about the situation. Her attitude and tone were very bad to the extent that she made a scene and was talking at the top of her voice. I proceeded to pay for the cot at the regular price but was very unhappy at the way I was treated.