Vodacom makes me pay for their mistake

I bought a SIM card from Vodacom and wanted to keep my old number (from Telkom) so I went in to the vodacom store in Constantia Village and someone helped me do this on a Sunday. However it didn't work and turns out you aren't supposed to do this porting process on the weekend, so it didn't work. on the Tuesday I went back to the same store because my SIM card wasn't activating and they told me the person who did the porting for me on the weekend did it wrong and then I had to pay for a new SIM card. Yes I had to pay, not Vodacom, the ones who made the mistake. I tried to get them to explain why I had to pay for their mistake but they were not hearing it and I wasn't allowed to speak to the manager because she was "in a meeting" and they didn't know how long she was going to be so I couldn't wait. Really felt like I was being ****med and did not enjoy the experience at all.