I have registered for a Plus / Premium account but I can’t post on the forum, register for events or access revision courses.
The first thing to check is your email inbox. In the confirmation message (sent by firstname.lastname@example.org) is a magic link that enables your account. This is an anti-spam measure.
If you have not already done so, click this link, then log out and log in again. You should now have access to everything you’re entitled to.
If this doesn’t work, or you can’t find the email, please log a support ticket using the buttons to the right.