Cant Cancel My Account

I called the call centre to cancel my account for my tracker, as I am selling my car. I was then transferred to somebody else who did not pickup. Eventually they told me that they could not assist over the phone and that they would SMS me an email address which I can email to have my account cancelled. I have not received a sms with an email address.

I then emailed the following email addresses which I got from my invoice ********** ********** and ********** I have not received a response that my account has been cancelled.