Cartrack accounts

I had a car track unit in a bakkie that I sold. Since the sale I have subsequently cancelled the contract and paid up the outstanding amount. Unfortunately Cartrack accounts department appear to be totally incapable of understanding this and finalising this account. I have been receiving up to 3 phone calls per day along with sms's and what's apps telling me my account is overdue and when am I going to settle it. I have explained the situation to goodness knows how many different people, I have sent e mails with POP to the e mail address given (***) and I have even sent e mails to specific people at Cartrack and still the matter is not resolved. Now I am receiving sms's from Viljoen Attorneys threatening a legal summons. Should Cartrack wish to go to court and end up with egg on their face that is fine I will assist them. I wish someone with the capability to resolve this issue can contact me and I will explain the situation one last time. If not then so be it. One just hopes that Cartrack are better at finding cars than they are at managing their accounts.