bad service and incorrect billing

On the 18th of sep my phones got cut off again by vodacom. After hours of trying to get hold of vodacom call centre I was told that there was an outstanding amount of 3300. I was surprised as my account is only due on the 1st of every month. Trying to get hold of vodacom again to get feedback as to why the lines got cut as payment is not yet due I could not get hold of anyone. Needless to say I paid the 3300 due just to get my phone back on as I have 3 small kids and I need a working phone in case of emergency. On modal I contacted vodacom to get answers and was told that the amount due was for june/July. So vodacom cur my line 3 months after with no warning contact what so ever. Now what I do not understand is that when my account is not paid vodacom cuts my lines until they get payment and only then they put the phone back on service. So how is it possible that there is an outstanding amount for 3 months back? I do not have money to pay vodacom double in one month I have a family to support. Who will be held responsible for the sep account? And why does vodacom punish customers for the incompatencies of employees? I need this sorted out asap