I can think of a lot of negative counterpoint to hypothesize the darker side of this situation and take us down the rabbit hole, but I’d rather wish you the best and hope that you get the best possible outcome. Perhaps the item is in the mail, you’ll receive it soon, and shortly after mailing it he went off the grid on tropical holiday and has simply been out of the email loop. There’s no way to know for sure but I hope you’ll update this thread with the resolution (or irresolution).
That said, if you tell me his name, I can go create an email account under that name and send you a message of reassurance if that will help. Unless the email account with his name which you received the messages from is linked to his business specifically I wouldn’t put much stead in that, and there’s always the off chance someone’s identity was stolen however this would be an extremely benign way to use a stolen identity which is part of why I can only hope for the best because if the person is a con artist they aren’t very good at it.