Cancellation of services

In October 2014 I phoned ADT to give them 1 month notice that I would be like to end my services with them and go to another service provider. I gave them a writen notification as well. ADT then informed me that I signed up for a 12 month contract. I would have to pay them a settlement value for remaining contract balance to get out of this contract with them. In response I informed ADT that the sales person never informed me of a 12 month contract and the quote he provided never indicated 12 months. (The sales person when selling ADT services informed me to give my previous service provider a 1 month notice) ADT is contiuing to debit my account - Increased my premium and yet have not provided me with the 12 month contract that they say I entered into.