Protect America When Equipment Fails - They send new equipment and make you extend the term. Texas

We signed an agreement in 2007 for home security.  In 2012 - the equipment was failing.  We called to get it fixed, and they stated that we need new equipment. When we received the new equipment, they unilaterally extended our agreement for another 3 years, or until October 2015.  We moved out April 2014 and I asked to cancel the agreement. Have been working with them for the last 3 months, and they dug in and won't let us out stating that we owe them until October 2015. They have produced documentation 'after the fact' - an entire contract that we agreed to their Termination Provisions.  We never saw this in 2012. They are scammers and will try to hose their customers.