If you cancel with 5days they blacklist you for a fine

I have been upto date with payments. I then decided to cancel because I don't see the use of having Cartrack if I set car watch and it's actived they take time to call at times they never call. I don't see the need of having car track. I then requested to cancel the contract on the 29th they advice me on the payable amount as in fine for canceling early. I agreed and told the lady I will pay it on the 15th to my surprise I get a notice of intention to black list letter before the payment date agreement. Now having paid on time for 2years and a half this is how I am treated. I will never ever sign up with this company it's the worst.