Promotions to good to be true

Tracker Connect contacted me on some promotion, on that promotion i was told that it will be charged at R3 extra month on what i was currently paying. When the time come to debit the amount it was more that what was agreed upon - R190 + 60 and my monthly payment of R221. All this came to more that R400 per month. I reversed the debit order and then i sent a query to Tracker. My query was not resolved and the next thing my account was handed over to Blake and associates. I feel ****** by tracker and they are not willing to resolve it. i was told that all the conversations were recorded and when i asked them to look at the matter seriously they didn't instead they kept on sending me reminders to pay. I cancelled the service with them but they still want me to pay, i have asked them to come and take out their device from my car because i do not want their service any more. Blake and associates keeps on calling me demanding payment.