Unhappy Customer : Netstars service is poor .

I called Netstar on 06/07/2021 to check if my tracker is still active , I just wanted to see if the Tracker is working and to my surprise the agent told me that my services have not been active since 2020 June or may , I was so shocked. Netstar have been debiting my account from 2017 till July 1st 2021 . For the past 3 years they were not debiting directly from my account as my Insurer mas Oakhurst , they were debiting directly from Oakhurst . Then last year February I cancelled my contract with Oakhurst ad I informed Nestar and told them that I wanted to continue with their services I even gave them my banking details . on the 1st of may 2020 they started debiting directly from my account till 01 July 2021 , I was surprised when the consultant told me that my tracker is inactive then I decided to cancel the my Services with netstar , I asked the agent If I owe them anything and she said no mam , your contracted turned 3 years in February 2020 so you are not owing Netstar anything she then gave me a cancellation reference number :CAS-***-H7Y4 . Nestar is busy debiting my account even though I terminated the service , they are busy sending me emails and threating me , im tired of Netstar , I have been a Good client to them from 2017 till July 2021 and I was very much disappointed and Im still disappointed . Can Netstar stop debiting my account please .