Being overcharged and ignored

My contract with Netstar was expiring earlier this year when I was contacted with a deal to renew my contract with a new device at a reduced rate. From the first month I noticed that my debit order was more than what I agreed to and I emailed Randy Van Wyk to advise. He told me the difference was due to VAT being added but I rep**** to him and mentioned that was too high, even if VAT was included. My emails was then ignored but my money was still being taken. I thereafter contacted the Help Desk and was assisted by Takalani who said he will raise it with the accounts department but again nobody contacted me and my money was taken. I recently contacted the accounts department and spoke to Jesila who advised she will bring it to Randy’s attention but still nobody has contacted me. Nobody willing to assist and I’m being charged R1500 more than my agreed contract.