Taking money from my account

After DSTV allegedly moved over to a new system, I have been having countless problems and shocking customer service. First it took them over a week and 21 phone calls to fix my E16-4 error, when my account was not in arrears, and costing me hundreds of rands in phone calls, as each time I was holding for around 20 minutes. This on top of not having television for a week....I have a Staff account and my account is paid every month on the 28 on time. Tonight Multichoice have debited R1751 from my account with no permission, not even a phone call. I don't have the funds in my account to cover it, so am now liable for bank charges, and a black mark against my credit rating. THIS IS THEFT! I can never speak to a manager when I phone, if I eventually get through. I know Multichoice has the monopoly for satellite television, so it seems they don't really care, because where else can customers go? Perhaps this will get a supervisor / manager to contact me, but it shouldn't get to this in the first place.