Your BlackBerry devices downloads multiple copies of the same email
This is a known problem with the BlackBerry Web Client. If you already have an Outlook web server under another account, the BlackBerry server automatically includes that service and creates a never-ending loop.
Reset the integration at the BlackBerry Web Client by enterng an incorrect password when attempting integration on the the BlackBerry Web client. This forces you to the next screen. You can now set up your account as normal as the BlackBerry server thinks that this new account is different from the previous server setup.