Forced debit order Mandate on my Capitec account by Netstar

Netstar just debited my account R819, i didn’t authorise that payment, i called Capitec and they said it was a forced mandate, i need my money back, I didn’t authorise any payment and i cancelled the tracker 2 years ago, because, i was using it with the car insurance, so i requested that they can change my account details, sending emails and calling countless times last year, doing nothing, so now they debited my account without me approving the mandate, i want my money. How do you do forced mandate on my account wherein im nolonger using your tracker. It’s been 2 years.