Can not close an account after the agreed period.

I acquired ADT service for the period of 1 year as agreed with the salesman and paid in full via EFT. After the agreed period has elapsed I have been receiving monthly invoices for an additional year.<br> <br> After several attempts over many months, with customer service and the accounts department, to sort this out I have got nowhere.<br> <br> I have been told that I must pay an early termination fee (a substantial amount) since ADT only does 2 year contracts and their system reflects I have signed up for 2 years. <br> Clearly the contact was entered into their system incorrectly.<br> The contract also states \for any agreed period between the customer and ADT".<br> <br> Since then I have obtained the services of another security company and disconnected ADT's equipment.<br> They have not even bothered to investigate this"