No proof of cancellation as requested.

I called Car Track 23 July, which was 8 days after my debit order went off. The reason for my call was to request cancellation of my month to month contract as I had sold the car. The lady insisted on a 20 days notice. To-date, I haven't received any confirmation of contract termination. The last time this happened, a wrong car was deactivated, and I was almost made to serve another 20 days notice for something that wasn't of my own doing. Can someone please have a look and send me proof of cancellation or an update?