07-21-2013 03:42 PM
Hi and Welcome to the Community!
With a strong carrier network signal (e.g., not merely WiFi), I suggest the following steps, in order, even if they seem redundant to what you have already tried (steps 1 and 2 each should result in a message coming to your BB...please wait for that before proceeding to the next step):
1) Register HRT
2) Resend Service Books (pre-BB10 devices only)
Hopefully that will get things going again for you!
If not, then you should try fully deleting and re-installing BBM.
Otherwise, you should contact your mobile service provider for formal support.