Something is not right with MTN,***********&unfair

On the 11/03/15 I went to MTN store(Nicolway) to do the sim swap as I had lost my sim card(contract). The lady who helped was friendly and she explained everything in detailed and said its for free(i.e. before it was paid and about 5 months ago they changed the clause),so I couldn't do the sim swap because I had forgotten my ID at home. Then on the 14/03/2015 I went to MTN Store(Jabulani Mall) with my ID to do the sim swap, to my surprise I was told that I have to pay about R135.00 for it. I tried to explain to the assistants that I went to Nicolway and they said its for free. They then told me that its free if I have the sim card and if I don't I have to pay R135.00. I then told them that I would rather do it at Nicolway which I did it for free on the 19/03/15.On the 22/03/15 I went back to MTN Jabulani mall to tell them about how I wasn't satisfied with their service and that's when one assistant tried to explained that at MTN Direct they do it for free, I even called their manager and she said an email was sent from Head Office to say that we have to pay for sim swap. Can someone please explain why do we pay to other MTN stores for a sim swap and we don't at other stores.