Bad service

I have sold a property which now is in the name of the new owner (account settled). The problem I have now is that the account is still active and still showing that I still need to pay mortgage protection plan,I have spoken to more than 4 different consultants asking why the account is still active and when it will be closed but no one is giving me a direct answer and they all give me different answers. I Asked to speak to cancelation department then the answer was that there is no contact numbers for that department I don't know what to do now.