One rule does not apply to all!

I went into Pick n Pay clothing at La Lucia mall to exchange and return a few items of clothing that I purchased on Sunday with my grocery shop. The cashier asked if I had a slip, and I said unfortunately not, as I purchased them with my groceries, however I did not see a problem as all the labels and tags were in tact! Her response was that I could not exchange or return as I did not have the slip. I asked if I could then speak to the manager. Her response was to point to a section of the store. I asked her why she was pointing, her response was that I must go and see what I want to exchange the item for and the manager will come! I selected my item and joined the que again. Only this time she was prepared to do the return without calling the manager?! Then the gentleman behind me in the queue got served and was returning an item, and said he did not have slip, the cashier serving him gave him no trouble in exchanging the item. I am highly annoyed and frustrated at the sheer attitude that I was given today! If you are going to apply this 'rule of returns with till slip only' (which i add is not in line with consumer protection act) it cannot be app**** to select people!