MTN bad customer service

MTN was not helpful at all, my mom's phone was hacked her number ****** and ported to a different network. When we reported to MTN they didn't take it seriously and told us to do a sim swop, how do you do that if the number is now on a different network. So I feel like our information is not safe on MTN their employees can use it as they like. I'm not happy at all they hacked their system to get our information but they act as if it's our fault.