Official RIM BIS Troubleshooting Steps
 

KB02169 - Unable to send or receive messages using the BlackBerry Internet Service

I'm not posting the content as it is ridiculously long and most likely going to change over time. This is a GREAT resource!!!!

Making this sticky; comment if this helps / if its useless.

Thanks for making Sticky!
I have forwarded that link to many of the staff at my company so they can try to sort things themselves ;-)

8-) Well this is cool, I have booked marked this for future references.

Thanks :smile: