From myhosting.com Wiki

1. Hard Reboot

a. Remove battery from the device.

b. Leave the battery out for at least 1 minute.

c. Re-insert the battery and turn on the device.

2. Register the host routing table

a. From the main menu go to Options

b. Select Advanced Options

c. Select Host Routing Table

d. Hit the BlackBerry button (menu button) and then 'Register Now'

3. Contact myhosting

a. Contact us at support@myhosting.com and we re-send from our end