BB Curve :: Cannot Setup New Email Account

I am a consultant and have a client that has a BB Curve. He has been using a certain provider inet for his email. He has now changed to a different provider (for technical reasons). I have tried to setup his new email account for the new provider - I also use a BB curves and have performed this operation for over 50 of my clients. However in this scenario, the Curve keeps asking for his account id and password. We have tried to enter it and it says that the Username cannot be blank. If we exit and re-enter the setup tool, and then enter the same info again, it says that the username and/or password is incorrect. His credentials have never - ever changed.

We cannot get his password (or acct info) sent to him by BB (RIM), because he no longer has the email address of record. Of course I tried entering a different email address to send it to, but of course it doesn't get to his phone as there is no eamil address setup (except his old one). The provider here in town (TELUS) has been quite useless in helping and have been quite specific that we need to talk to RIM, well of course this seems to be the only avenue available.Can someone direct us to the appropriate area or resource in order to proceed with setting up his new email account.