Car track hounding me

Car track has been hounding me everyday for over a year for R436 which is a cancellation fee when I cancelled the contacts which had already come to their natural end. They say a months notice must be given. So they want this R436 for the notice period not for actually providing a service. I have made numerous requests for a manager to call me (and not once got a call back from a manager) so we can discuss writing off this amount cause I have lots of other debt piling up that needs attention my business is dead due to COVID-19 and no tourists. I paid them for years and never once used their services the least they can do is waiver this fee or put it on hold until after Covid when tourists return. They seem to be willing to spend more than R436 just to get me to pay and now I’m being threatened they will hand me over to lawyers for R436. The worst tracking company… had repeated issues when first installing the device, they had to come out several times to fix it resulting in loss of income on my part I was understanding of that