Top-up contract says insufficient credit

Since the beginning of June our Top up contract says insufficient credit to make a call, yet when we called the call centre we were told that we have a balance of R385.09. The consultants put us on hold but cannot give us an explanation as to why we cannot make any calls. After calling about 5 x i have decided to try Hello Peter. At the last call the lady, whose name i cannot recall, confirmed again that there is a balance but she cannot understand why it says insufficient credit. It is frustrating that Telkom cannot provide us with an answer and in the interim we are left without outgoing calls and my mom is alone at home during the day, what happens in an emergency?? All we need is to know whats the reason and then take it from there.