Sim card charge!

Yesterday, Sunday 14 June 2015, I went to get an upgrade on my cell phone contract which has expired February already. I needed to do a sim swap and my husband was quite frustrated that we had to pay a sim swap fee of R70 (on top of the R150 upgrade) as no other provider charges for this. This wasn't even a network change, it was a Vodacom to Vodacom contract change, of whom I've also been a loyal customer for many years. We paid the fee, however I've been reading everywhere that a sim swap does NOT cost you except for the sim card which should be a mere few rand. I'm frustrated as I feel almost like the consultant ****med me or something. Why did we have to pay this fee?