bad customer service from Store manager

I was in Westgate mall branch in Mitchell's Plain Cape Town,I'm quite disgusted with the way the store manager Vanessa Adamson handle the situation,as a customer of Mr.Price it is not the customer duty to check if stock that they merchadise onto rails correctly. I as the customer if it's on the shelf merchadise as a banded pack I assume it is sold like that being satisfied what I took from the rails,I went to go purchase the goods I had ,as we come to the shorts that is merchadise as a banded pack the cashier says he needs to go and check the barcode,as I'm waiting for quite a few minutes already only then the Store manager offered to assist,patiently waiting for another few minutes she then called for one of the assistance and she went back forth,me having to wait again,she then they told me that it's not a banded pack and it should be matched with another colour,I then told said after the long wait I would really like the one that was on the rail as it was not my fault that it was incorrectly merchadised and that the shop assistance should have picked that up,and not make the customer wait so long only to decide they not selling it like that,the store manager not even apologising for the inconvenience caused,said to me that they can't sell it like that,so making me wait and not being knowledgeable of their products was of no concern to them,she the store manager then said that there are 100s of products and she count keep count of all the products,first of allit's not my fault for there poor execution.and how incompitent the manager sounds to say she is not aware of her business how serious is she really taking the Mr.Price business and the type of management they employ how serious are they are about their business,according to the CPA act ,once it is merchadise /displayed on the shelf for consumers to purchase consumer can buy what theysee ,unless otherwise illustrated,she made their mistake mine .Clearly they not serious about keeping and gaining more customers.