Meg,
There's a few easy things that can cause the login functionality not to work. We'd need more information to help understand the issue though. Can you please let us know exactly what versions of Joomla, JFBConnect, and K2 you are using?
Also, please post from the account you subscribed to JFBConnect from. Priority support is for active subscribers only, and the account you are logged into doesn't look to have every had a subscription to JFBConnect.
Thanks,
Alex