In order to get to the BASC-2 Online admin dashboard you need to first login using:

https://tpc-etesting.com/BASC2Online/Login.aspx 

After you are logged in, erase "AccountManager.aspx" from the end of the URL and replace it with "AdminDashboard.aspx"

The address will now be: https://tpc-etesting.com/BASC2Online/AdminDashboard.aspx

Press ENTER and this will take you to the BASC-2 Online Admin Dashboard where you can unlock accounts and do some other admin functions.