Taking Advantage of the Elderly

My elderly Mom has been using MTN for years. She took a contract and once it was finished she paid MTN off but then her number is blocked for no reason. She can't make calls or receive and send text messages. She's been to store after store, made calls to Customer Care and was told to pay even some more money. For months she's been struggling with people telling her "We've never seen anything like this" Well that never resolved any of her issues...Bad service I had to go this route just so I can help her have this mess sorted out.