The part that bothers me about this whole story has nothing to do with email vs snail mail vs phone call or the details of discovering a flaw, or the rapidness of responding to a customer complaint.
Why in the world would "filler" even be present at the L-N factory? At the prices they charge for their tools, the customer has a right to expect a product that has not been patched up. If the tote was imperfect it should have only left the factory in the trash bin.