Horizon Services...'we had a successful install...it was a defective part...'

As my headline states, Horizon replaced my 21-year old furnace and less than two weeks later we had to evacuate our home because of a CO leak. The company sent out a tech that day who spent nine hours at our home fixing the problem. He stated two defective parts were the reason for the issue (CAD cell, nozzle valve) and that it was resolved.

My wife and I were livid obviously because...we could have died (was as high as 40 ppm in our basement), it was a brand new unit that we paid a smidge under $11k for and the company has repeated this line, "we didn't do a bad job, it was a defective part from the manufacturer..."

I'm not a contractor but in what world can they make such a claim? Also, we were seeking financial support for the egregious issue and their proposed resolution, "we could drop it to $8k..."

I'm seeing red at the moment and feel like I should just contact a lawyer. I'm tired of these companies doing these things and treating it like it's not big deal.

*Also wild that the general manager said, "I don't see why your problem is with us, we had a tech come out and fix it..." Ah yes, you sent someone out to fix your mess...here's a gold star!*