Horizon Services review: Lennox furnace

In June Horizon installed a new Rheem HVAC Split system which took weeks to get it to operate correctly. However after multiple tries and several visits, they were unable to get the HVAC to connect to the backup furnace which takes over when the temp gets to 35 degrees. On the techs last visit on November 18, I was told they had no more answers to why it was not responding and had to consult with a Lennox tech and they would get back to me the next day. No one called me back and I have called several more times to get answers and each time I am told someone would call me back. Today the temp outside was 10 degrees, the temp in my house was 3 degrees. No response and no help. Still waiting for an answer. I have been a loyal customer of Horizon since 2010 and have spent thousands of dollars with this company.