BIGGEST MISTAKE UPGRADING!!!!!

2 Months ago i went into Altech Autopage in N1 City to check my upgrade date. They advised that i could upgrade early by 2 months. On my previous package i was on a Top Up 100. They advised me in store that i would be on a Top up for 4 months as my migration date was set for the end of June. The amount that was supposed to be debited from my account monthly was supposed to be R399. Automatically i have been placed on a open line and recieved bills ranging from R1000 - R1900 which is disgusting! I went into a branch that advised me that they were aware of the issue and i should contact the call centre for a credit and that i wont be held responsible for any of the charges. I have been to numerous stores about 20 times and called the head office, requesting to speak to a manager but nothing has been done. When speaking to a lady she has also given me specific information about my account without going through DATA PROTECTION! My debit orders have come out even though i as a customer have not requested for this. I have not given authorisation for this amount to be taken out of my account. There is a bar on my phone now and i cannot call! I need this fixed!!