its not a phone issue, i suspect you don't have a connection to the BlackBerry Infrastructure..... without a data connection your pretty limited to what you can do. are you able to browse the web or send/receive emails?
you live there or on holiday? if the later you need to roam onto a partner network of your home provider that allows a BlackBerry connection.
you sure you have a data plan on the number?
are you getting any error messages?