Cartrack debit order *****

Cartrack debited my account for an amount 2 days ago after I have cancelled the service a year ago, I did not receive an invoice or statement once notifying me of any outstanding amounts, then received a whatsapp that I owe them a ridiculous amount after only having the service for 3 months. I cancelled the service due to no response from them after my tracker tested faulty and waited 6 weeks for any feedback. I called their offices 2 days ago and the consultant confirmed that I don't have an active account.