Just an observation...you most likely wanted a few buildings and hired a builder to erect them (I know a guy that tried it on his own and broke his back in the process...came off the roof in a light drizzle)...your GC most likely dealt with the truss people. IMHO, don't leave either of them off the hook until you get what you paid for. And a dirty little secret is that the cost of a truss is???...(hint...not much)...probably costs more to deliver than what is in the materials (that is the magic of trusses).
Oh no it is not over yet. However right now I need the GC on my side to get the problem solved. Then we can talk about what kind of a discount I want as a result.