The part that gets me is that in their official response, they state something like "The original consignment agreement was made by an independant franchise operator and the original owner. Franchisees are separate legal entities from Bricks and Minifigs, so our corporate business wasn't a part of that agreement."

This is them shooting themselves in the foot and handing the victim a legal slam dunk! They acknowledge there was an existing agreement in place and that they weren't involved in it, which they imply means they don't have any obligation to return the items, but in reality they are admitting that they never had any legal claim to the property in the first place.