Unresponsive device, not responding to queries and handing over a client to their lawyers for non payment

I had a tracker with Netstar in January 2018 and the device has been unresponsive and they used to send technicians to fix it over and over again, with the number of complaints I had, they gave me a payment break for over 5/6 months. I still experienced issues with their device, they changed my tag and panic button more than twice and I still had issues. They re - installed my device in 2019 and assured me that it will now be fine. They stopped sending my travel log book in December, at times I'd receive a different location from where the car was. I got tired and stopped paying in as they were not responding to my queries.

The excuse of not responding to my query was lockdown. Now they handed my account over and I told their attorneys the reason why I stopped paying since I didn't know what I was paying for, I don't even know if I had an active device with them since I had a series of problems with their device and them having to change re-install it and giving me a payment break for so many months and incorrect location of my car. Their early warning sign app also stopper showing me results before I even stopped paying. I asked their attorneys to contact their client first to get the records of my profile, since I've said that, they stopped calling me.

Netstar could not tell me if I had/ have an active device with them before they handed me over to their lawyers. They could not tell me whether they deactivated it last year or if the one they re-installed was working properly or if was just a temporary fix which had to be attended to monthly or every second month.

Am I not supposed to get a service that I pay for? How does Netstar expect a client to pay for a non responsive device?