MTN CELLPHONE CONTRACT ISSUE

Please kindly assist my Aunt she has 2 cellphones contract with MTN Heidelberg mall every time they get blocked and she is paying for services that she is not using and the matter has not been resolved they always promised her that it had been resolved but she keeps on encounter same issue she can't make calls she only receives calls her first contract she took it last year March and the second one this year August it's been 3 months now having same issue after they have fixed the issue it only last 3 to 4 days and get blocked again. Customer name is Mnguni Margaret Smangele *** cell phone number *** and *** You can use this email address ***