Unauthorized money out of my account

Good Morning <br> My name is Martin Volschenk, I have a account for the past 20 years at Vodacom and I took out a new contract end last year.<br> They made a mistake with the contract and I only realized it in January 2015. I went to see them and they promised me to rectify the problem. In Feb 25, at 09:19I received a sms \+***@Vodacom Notification: a credit note for account number ***7 has been processed for the amount R 3635.43(Excluding VAT)<br> No money was paid into my account. My normal amount that I pay is around R1150 per month. On 28 feb 2015 they took out of my account R5304.00 and my normal instalment is only R1150. Now I have lost my credit rating at the bank because I did not have enough money left in my account for the debit order to go through.<br> I went back to see them on 01 March 2015 and after long discussions they will look into it only on Monday by the manager. She let me know that the difference of R4150 will be paid into my account only in 4-7 working days. I still did not receive the credit that they said. When I confronted the manager on Monday the 2 march 2015 she said this is a new matter and will look into it. Can you please advise."