Hello,
I am using BB9700 (OS 6) with BBM 6 installed on it. I had received an invitation from a friend on BBM which I accepted. She now does reflect in the BBM Contacts list however the request is yet stuck. I yet see a pending request from her. How do I remove the request? I have tried delete as well as accepting/denying it but it is still stuck!
From what I hear from her, my contact automatically disappears from her list after some time. She is on BB Curve using OS and BBM 5.
Try a battery pull; take out the battery while the BB is on and put it back after 5 minutes or so.
But I think there's something wrong with your BlackBerry. I have had the same problem with my previous 9700 where it was deleting certain contacts by itself, so I have asked for a replacement and got one.