Hey! If the users are awaiting email confirmation. Look them up in admin cp, and under Actions, click "resend confirmation email."
Note: The user state needs to be awaiting email confirmation
I would prob go to admin cp -> users -> search and check just the PENDING EMAIL box. Then go through each record and click RESEND.
I use an add on for our forum that automatically re-sends after 3 days if they didnt complete the email registration by then. After 21 days, it deletes the account.