Charge ld for non working tracking unit

Netstar is charging for service that is not being provided and always passing the buck not wanting to take accountability.

Have a tracker since January 2021. After 3 year contract i was told contract will be month to month however was not told the unit has to be replaced. Only realised on the fourth year that the unit is not working abd has since being trying with no luck to get my refund. Only when i complained they want to replace the unit that in their own words "its working perfectly"

To top it all ,they still want to charge me when i want to cancel even though i requested cancellation upfront