you should be able to sign in separately on SB (if they haven't closed it down completely) and send messages to people on your list of friends. But the system is always on the brink of collapse and I don't bother trying to get in there to read messages anymore - life's too short
Go to the SAB, enable the private messaging in your profile, then up on the top right will appear a friends listand inbox. Go to that but and add a friend, type in the username and once they have accepted, youcan exachange PM's.
SAB is sports answerbank, Jayne - click on Sport and it takes you to a separate sister site where you have to sign in separately with your AB name. Many interesting questions about football.