If it is just the sending of emails that is not working, on your Blackberry, does the sent email message show up with a check mark or red X?
If it has a red X, open the message and at the top will be an error message. Then search that error message here: BlackBerry - Support & Services
If it has a check mark or still unresolved, on your Blackberry, go into Settings>Options>Advanced Options>Default Services.
Try changing the default Messaging CMIME service book to the other options available.
Feel free to post back with more information or what worked or didn't.