Overcharges on contract and vat amount

I shudnt even give them a star !!!!! Vodacom are the biggest ******* ever ... Firstly we took two contracts for 200 each no data no airtime for huwaei y5. Vodacom charged 1400 and now 1040 ... I called the first time to query they said they will rectify ..no log was made ..I called now the second time still no log but I threw a fit and the lady gave me a ref no ... Apparently on the one contract they added bonus airtime and bonus data ..now whose problem is that ... Nevertheless I asked for it to be cancelled .... I asked for a detailed break down 442.63 6.08 264.35 8.69

I get a total of 721 .75 plus vat at 15% should give me R830,01

So that brings me to the question where does Vodacom get 1040 from and the 1400last month ??????

The call centre agent says it's miscalculation....I want my money back and I think Vodacom should be reported to sars for adding extra vat ...