Handy Air

Mr.C*** came out in early February to discover that our thermostat was not working.... no heat. He never came back nor returned my calls.
We have had no heat since our system has been installed. It was found out this second time that the thermostat needs to be replaced, it is not communicating with system out back. Each time we have cold weather our house is freezing.I have called and called no returned messages, left a review on website no response. Looking for an address to send a registered letter. Please help us if possible don't know what else I can do.