When a Security System Isn't Protecting Your Wallet Dear ABC News Fixer: Back in August, a sales rep from Vivint knocked on my door. Since I was already looking into getting a security system, I found this to be opportunity knocking. What sold me was the thermostat and light control feature you can access from a smart phone. Before I really had an opportunity to think it over, the salesman had an installer on the way. All said and done, I thought $68.99 a month was a good offer. I signed a five-year contract under the assumption that they had tested everything and the system worked. Then, in October, it started to cool down outdoors and I tried to get the thermostat to work. It wouldn't turn on my heat. I called Vivint and they sent out a technician. He discovered that my house is a two-phase system and the thermostat is a three-phase system. In other words, it is not compatible with my house. I bought and installed my own thermostat so I could keep my pipes from freezing. I tried to get out of the contract and was told I owe over $3,000 to cancel. Around that time, we had a separate problem with the camera and light control features. I called Vivint again. They offered to lower my monthly fee to $60 and take away the thermostat and light components -- the key features that sold me on the system in the first place. After arguing my point this time, the early cancelation fee dropped to $2,073.66. I don't feel I should have to pay that to get out of a voided contract. Eric Poirier, Rifle, Colo. Dear Eric: Common sense says that if the service you bought can't function in your house, you ought to be able to cancel. We had a little better luck getting your issue up the ladder at Vivint, and we're happy to say those folks agreed. A Vivint spokeswoman said the service tech should have realized the thermostat wasn't compatible during installation, and she apologized for the mistake. Vivint said they would've preferred to keep you as a security system client, but given this incompatibility issue, they've agreed to cancel your contract with no penalty. For anyone considering a home security system, here's some advice from the Federal Trade Commission: Get recommendations from family, friends and neighbors. Compare written estimates from several companies. Find out who will install the system and who will monitor it later. Ask about penalties if you move or need to cancel for another reason. Ask about warranties, and find out whether the company or the manufacturer will handle that. Make sure the sales contract includes any promises made by the salesperson. Call your local police and fire departments to find out whether you need to register the system and whether there are fines for false alarms.