Pick n pay not sticking to their policies

So I was at PicknPay Ottery hyper earlier 2day,shopping but on top of my list was a kettle since my stopped working and guarantee was already finished, likely there was a Aim brand glass kettle on special for R279.00 all and good bought the kettle, but as am some1 who checks the slip this time was no different and I informed the cashier that the price was wrong as it had scaned 4 R399.00, the advitised price was the 279,so the packer went to investigate and found the R279 displayed and brought 3 of the displayed barcods with and left me at customer services and I say ow you still have Double the difference, the lady said no that's out by the door and I asked why do you still have a big board hanging over your head if thats the case (she had no name tag) another lady came out of a door that was behind her said that only apply if you buy more then 1 iteam, I still reminded her that nothing that is displayed on their notice said such (anyways how was i going 2 buy more then 1 kettle) A manager was called and told me that he could not give me double the difference cause that did not apply to appliances and still asked where is that written cause the board spoke of no such and Verndre(was his name) said its no use us arguing cause i was not going to get double the difference. Now my question is had he already concluded that I was not going to get double the difference, even though I was right or doesn't apply to certain people 3 things was said to me while I was there 1.Double the difference is out by the door 2. I must buy more then 1 item 3. Double the difference don't apply to appliances