Open a case at the police station , we cant help you!

My mother got her MTN number hacked and the person who hacked her line managed to access or create a WhatsApp giving her access to her contacts. That person proceeded to ask people on WhatsApp for money pretending to be my mother claiming an emergency with her bank account saying she needs money urgently via cash send and would pay these people the next day once the issue has been resolved, Once we found out what was going on we went to MNT Thavhani Mall and explained what happened requesting that they assist( that was on Friday 06 /09/2024) , they claimed to have cancelled the number and issued us with a new sim saying its a sim swap, Yet upon receiving a WhatsApp message from the number again last night we discovered that the number is still active and nothing was done about this issue, while we where thinking that the line is off due to Sim Swap, the number is active and the **** continues.This morning we went again to MNT Thavhani Mall to report the issue only to be told this time that they cant deactivate the sim card as long as the person is this actively using it advising that we go to the police and open a case on the matter, This is a frustrating issue that needs serious attention yet an International service provider is failing to deal with, MTN what now? is this how my mother looses her number and how can you not trace who this sim is RICA with ? how safe is our personal information out there?