Vodacom overcharging no assistance

I recently took out a contract with Vodacom and everything went fine until I got a call from there call Centre advising me that they were moving away from SMS and that they would convert this to airtime. I was very upfront and told the consultant that the phone contracts was taking out for my daughters and that I did not want any additional charges. He advised me it was a straight swop. Two months down the line I noticed I was being charged and additional R350 for my contract. I called the all Centre and they advised me that my contract was migrated to another one and they would revert it back. When I received my bill no changes was done I called in again and another consultant advised me that nothing was done and he would resolve this. My bill came the following month and nothing was done. I called again but was still overcharged. Finally someone assisted but advised me he could not change the bill and I would be overcharged again.The next month I was o recharged with R75 and I decided to go into the shop I took the contracts. I was told that they had not migrated me to my original package as there was a promotion when I took it out and the chances I would get my money back was near 0. She logged a call and they have overcharged me again. Last time I will be dealing with this company they are a bunch of tbieves