Charging more that your goods are labeled!

I visited your Key west branch on Saturday. They are having a clearance sale. I bought a black pants that was marked down from R349 to R229.00 I charged it to my account. As I was walking out the store I checked my slip and noticed that they had charged me R299 instead of the R229 on the label. I went back to the cashier who told me they must've made a mistake on the mark down sticker and she cannot do anything about it. I am a reasonable person so I accepted this even though I was not too happy but I know that it could be human error maybe swopping the two numbers around. Later the same day I went back to the same store for another item that I was still deciding on earlier on. It was not marked down It was marked at full price. I get to the counter and once again it is more this time almost 150 more. The cashier tells me that they are doing mark up on some items and she thinks that this is one of them and that the label is wrong. Once again I am told she cannot do anything about this anth that It is my choice; I can take it at that amount or leave it. So I left it and left the store. I am very unhappy with this and feel it is completely against CPA.