email stopped working, can't set up new account

I have a Curve 8310 on ATT and use small business exchange.

My emails suddenly stopped working on my BB. I logged in to the ATT site and it wanted me to validate the account. After unsuccessfully validating it, I deleted the email account expecting a simple process of setting up a new account. My email, password, mail server, etc. are all correct according to my IT guy but neither the ATT or RIM customer support can get the email address authenticated and validated.

I, RIM, and my IT have been working on it for a week. We even set up a new profile on exchange and set up the test account successfully and did some test emails on the BB. any ideas? TIA.

I have never used Small Business Exchange so this is all specualtion.

If the email functionality uses the BIS service books this could be true, I have seen some of our users who bought a device off of ebay or from a friend and the previous person setup an account on the BB through the wireless carrier and that email address stays associated with the device even after a wipe. AT&T may need to completely remove your email address off of your wireless account so that you can add a new one too it.

Again this is all speculation.