Sounds more like they simply have an air bubble in the cooling system.
I doubt any complaint to the AG will fly. From this and your other posts, it's obvious you've been in contact with the service department and authorized the repairs.
Have them bleed the cooling system to remove any air pockets and your overheating issue will go away....Dennis
On edit: Maybe your overheating is still related to the "other" failed repair from the other facility that forgot to reinstall the box when you took it to them for overheating...:h...just a thought.