I had them put a new unit in my loft condo 4 yrs ago. I've had a renter in it ever since. I recently sold it and upon the real estate inspection they found upstairs register not working. I sent SE over to investigate/fix and the guy says the duct isn't connected and never has been. They are wanting to charge me $ to go into the wall and fix. This is such BS! That vent always worked when I lived there. I changed the upstairs filter regularly. The renter just never noticed or cared. If it was never connected how did it pass at least 3-4 other inspections over the last 16 yrs?! What can I do? How can I fight them?? Help please.