Excessive Billing and ********* Business Practice

I app**** for an early cancellation of my contract as I was selling my car in September 2013 in month 16 of 36 months of the contract. As CTrack always took all payments on the Debit Order instruction, I assumed that the cancellation amount of less than R1k would be debited off my account. I missed an email from them responding that I had to do an EFT and if they didnt hear from me in 7 days the contract would continue as usual. I was subsequently working abroad and they continued to take +-R228 per month until March 2016, being roughly R7k and to the end of 36 months and another year for good measure. They decided to stop taking the stop order after the March 2016 debit order came off but raised another 3 invoices, which they didnt take off (I suspect because their mandate didnt allow them to). They then instructed some ************ attorneys to chase me for R686 being 3 months that they stop debiting me for. The attorney now claim about R600 in fees??