Well, I was just about to backup my contacts by DM, and noticed that a lot of my contacts disappeared. These contacts were restored by an old restore file. Could it be a possibility that the ones who disappeared were inactive, and not in use anyway? Some of them had no display picture.
were they all contacts that you know as a fact still have their BB and have spoken to recently? some people i have in my list have eventually turned "greyed out" indicating they were no longer active on BBM and BBMs to them never delivered. sometimes people dont backup/restore their BBM lists when they get replacement or new phones. sometimes these have "dropped" off my list before. maybe these were people that migrated to other phones and forgot to do something about it.
I would simply request them again using their email address. They may have changed devices.
Pain in the neck, but if they're good friends they're worth the effort, right?
