OH MY HOW MTN IS FAILING DISMALLY WITH CUSTOMER SERVICE

I have been trying to get through to a customer consultant to no avail. It appears that they have all disappeared. I am trying to find out why my friend's SIM card is not working. She went to an MTN store only to be told that her number was allocated to another person. HOW IS THAT EVEN POSSIBLE?????

I would like to know why the SIM is not working.... she has to get urgent messages on the phone with her MTN SIM.... what now. Is there anyone, anyone that can assist please. DISAPPOINTED!