Not Receiving Activation Email

I have a campaign on Epic Words and have invited my players, almost all of whom were already members. My son is in the campaign as well, but he has been having problems getting his account activated. He received one activation email, but when he attempted to use the code provided, he receives and error message that the code is invalid. He's requested a new activation email, but it never arrives.

He's gone so far as to attempt to register with a different email address, but he still never receives the activation email. He's tried contacting Epic Words via the Feedback messaging, but has had no response. How can we get some help?