Cartrack

I phoned cartrack to cancel one of my vehicles that was sold, they quoted me a settlement and deducted from my bank account, after cancelation I got an alert on the vehicle, when I phoned cartrack I was informed that said vehicle has now got a higher amount to pay for cancelation, I informed them that i paid the quoted settlement they have given me, a settlement given to me by cartrack while having my details in front of them , they can not answer me, I have asked for the documentation on how settlement was given and for my account by them, but they ignore that part on various emails and keeps on sending me a cancelation form, I did not ask for My point being 1. I phoned cartrack to cancel a vehicle 2. I was quoted a settlement and cartrack deducted the amount from my account 3. They refuse to send me proof as to how the settlement was calculated 4. They refuse to answer my questions regarding this via email 5. I have asked to only be contacted via email from them since I do not trust cartrack anymore