Bad business service by Cartrack

I had unresolved issues with Cartrack since the beginning of 2018. I decided to stop doing business with them because i was not happy with the tracking device they put on my car. It was not working to my satisfaction, i decided to stop paying the premiums until they address my concerns. Cartrack adressed them two weeks ago. They have been threatening to take the matter to their legal team before addressing my problem. One of their urgent called me and we made payment arrangements. Cartrack carries on sending threatening sms' even after i made arrangements. I am not happy about their service.