Owes me over R2200 and won't pay up!

If I could give them no stars I would. I cancelled my tracker with them twice. Still they didn't cancel it, but kept charging me (Month to month contract). Eventually I stopped my debit order. Then they started contacting me... Finally they admitted that they were wrong and that they owed me over R2200! I had to get my own bank statements to show the debit order going off for over a year. Yet, their lawyers keep phoning me about my "arrears" (because I cancelled my debit order) and they seem to know exactly how much I "owe" them. Their credit controller doesn't get back to me after numerous phone calls to at least get a letter from them stating that I don't owe them money - I have to send this to their lawyers myself so they can stop calling me. It's just bad service from beginning to end! Do not use Tracker!!