Jet at daveyton mall . Johannesburg

My mother has problems with jet. Her account increased monthly but she pays every month. Wherever she goes to jet and complain the employees become rude and refuse to help her. They say she took an agreement of airtime if which she doesn't know of and she asked them to cancel it ..as her balance doesn't not decrease but they refuse to do so. Because the number the send airtime to we don't know it. The employees and the manager are so rude.