Forceful ******** debits

Agitated by Cartrack forcing a debit on my car

I've been getting threats from Cartrack regarding a payment. Two years ago an agent from Cartrack called & said the device is paid up and that I was on a pay as you go option. Now from August 2017 there's rude calls from lawyers people I have no dealings with threatening me to pay for this. I called Cartrack & no one wants to explain this situation how is it that Cartrack wants to garnish the NCR rule says the garnishee needs to sign & I haven't signed anything with this regard this is ******** without having further information about this prepaid method I was once told of. I'm highly disappointed & seek counsel. L Nkambule