Bad, poor and disgusting service

I went pass Clicks Southgate Mall and saw a special for 2 Sunlight 750 ml for R60. I then took 4 as this was a great deal. When i got to the till and after the cashier rung my goods up, he then tells me that the special only applies to the Sunlight regular 750 ml and not Sunlight 750 ml nature. I got the advert from the display and it clearly said 2 Sunlight 750 ml for R60 and that's what i wanted and why i took the Sunlight nature. It did not say which one. He called the manager whose name is Fikiswa who proceeded to insult my intelligence by undermine me by telling me that the one on special is green and the one that i took is yellow meaning that the regular was on special and not the nature one i t took. . Instead she quickly took the print away that advertised the 2 Sunlight 750 ml for R60. The advert clearly stated again that its 2 Sunlight 750 ml for R60 not 2 Sunlight Green 750 ml for R60. I asked that i want it at the price im seeing it for and was told by the said manager, Fikiswa that, in her own words, "It is what it is". I asked her to repeat what she said and she repeated "It is what it is" with attitude and walked away. I felt like a fool in front of all the other customers and her staff because of how rude and belittling she was towards me. Im actually shocked and disgusted at the service i received from such a reputable brand as Clicks., namely the Southgate mall store