Phone number ported

I am very upset with MTN and its inadequate services. My mom's number has been hacked more than once. The second time around we are informed that it has been ported to CELL C. How do you allow this to happen? When the rightful owner wants to do a sim swap, you ask for all the impossible questions, however, you are not able to do the same on ****mer. PLEASE RESORE THIS NUMBER AS SOON AS POSSIBLE. Your customer service and security measures are disgusting to say the least.