Hi there...
I need a little more info from you to see if it can be narrowed down... have you still got the problem? has it just happened out of through blue? was your device working perfectly before this? can you receive calls/texts?
Is your membership running? have you still allowance left to make calls/texts? (check your 48 members page after logging in-details to top left hand side-if all the above is ok, next step is power off your device for 5 minutes, and power on again-it may need the reboot to get you up & running as normal again...
Can you reply if this has worked for you?