Appalling service

I took a policy with this stupid company telephonically and cancelled it same day in fact few mins after I took it changed my mind, still they came to fit the tracking device in my car, had to fight with them to come take it out which they did after a day of sending technician even though I cancelled. Now manager called to apologize all was done tracking device was uninstalled, now problem is they trying to debit me I see daily they come and they want to take R2910 which I don't know what for which left me with unpaid charges with my bank of R-200 which I'll never be liable for as a bank employee and I keep getting sms that they'll come back on the 15th to re debit . I need someone to explain what bull**** is this that netstar is doing