Bad service

So this story is long. But I will try to cut it short. About 3months ago I wanted to buy a bakkie and for the insurance part I had to install a tracking device. So the company where I was going to buy the bakkie suggested I make use of the MixTelematics Matrix system. I payed for installment and then even before the forst monthly payment was to be deducted I phoned them to cancel it as I was not going to buy the bakkie anymore. They asked me to send an email with all information needed to cancel and so I did it. I received an email back giving me a case number. Heard nothing from then and then money got deducted from my bank account. Phoned them again and same story. This has been going on for three months now and they still haven’t done anything. I have phoned them multiple times today and no answer. I am very upset and this is just the worst service I have ever seen.