Worst customer service

I've very disappointed about car tracker I have confidence at first towards only to find out I was deceiving myself. They gave me wrong contract 2 days later they send messages saying am owing. I reported them since that day they said they will get back to me they're solving the issue. I spoke to more 21 people from the company I end up going to thier head office in Ranburg or Rosebank, they said a same thing. Four months later they say I should pay for a debt before they fix thier mistake but i have been reporting this almost everyday since the incident happened otherwise they are threatening to blacklist me. Meaning that what's they wanted of which am not threatened