You would be right in that regard. However, from how they described it, it sounded like they are having a problem with the activation link working within the first e-mail they had received.
So in that regard, the error they received would either come from the link being outdated, as it may only work for a certain time frame, or because their account had already been verified.
In both cases, the recommendation would be to locate the button within the account settings to check the verification status and/or send a new e-mail.