I highly questions the defamation excuse. 1, having a "legal team" would really hurt their pocket book and 2, to coincidental that it was "lifted" that very day of the email lol. I think the shipment was held on purpose and the defamation thing is a strong arm tactic to get him to stop bad mouthing them. As long as the guy isn't making up stories or stating un-truth as fact, there is nothing the company can do about it.
Some things are meant to be closed. Your mind isn't one of them.