Useless service provider

How can a perosn do a sim swap on a number that doesnt belong to them ?? But when I am trying to get my number back you guys are telling me that you need an affidavit ( weren't you supposed to ask this from the person who did a sim swap on the number that doesnt belong to them) Vodacom is a useless network provider because the security is not even confirmed.. I mean if a person can easily do a sim swap on my number while I am busy using it this means they have access to perosn information