With holding my voucher

Hi I have just been to a vodacom shop and according to them the is no such thing as 'clowning' a sim card and once you have done a sim swap the other sim card gets de registed immediately, i could not get a letter as they say its general knowledge. So please guys can do your own research and call Vodacom to ask this general information. I'm getting a feeling i'm not being taken serious because i'm black, cause I know a white person would have been called and this would be resolved.