Home Buliding and Interior Design

One of my custom builders has built this one house over and over again at least 25 times over the past four years, and on one particular house there has been mold spotted near some of my registers. I have met with the home owner, builder and mold “specialist” and we have all come to a conclusion that the blown in insulation had not filled all the cavities around the buckets in the attic. All great and grand for me all we had to do was take all the old duct, buckets, plenums, coil and heater out and replace it all. They get all the prices together and send them to the insulator and he refuses to pay the back charge because he didn’t see problem before it was fixed. Now my builder has turned on me and I am afraid I am about to get back-charged for crap that I didn’t do. Does this suck or what? I guess that’s why I have to carry liability insurance even though it’s not my fault. Has this kind of junk happened to anybody else out there?