Unfair treatment

I recently received a bad TREATMENT at Cartrack regarding my ACCOUNT, In 2021 November I received a call from CATRACK saying that I qualify for a 80% discount, I paid that amount which was R 1600, So every after 3 to 4 months during 2022 I used to call to test my unit everything was fine I had no problem, until now March 2023 trying to test the unit I was informed the my account was a BAD DEBT the can't help, they said I was blacklisted in October 2021, OK I then I ask why was I black listed while you guys gave me a Discount on my account and why are still debiting from my bank account till to date? Why 2022 I was able to use your services but now I can't? You contact cetre egency and account department are unable to explain on what's happening on my account, Funny enough I am still using the same account I had with them from the start, I belive CATRACK is not transparent to its customers and the also don't have a sense of emergency in providing feedback, I need the issue to re resolved.