How do you cancel ("developer reject") a submission to BlackBerry App World?
Not sure why the Barney Fifes of Stack Overflow are downvoting and voting to close this relevant, important and previously unanswered question, but..
I found an App World Vendor Support contact form here:
https://www.blackberry.com/profile/?eventId=8109
From the Issue dropdown, I selected "Vendor Portal - Manage Applications / Application Submission" and Issue Type "Release - Release Management". The other appropriate option would have been Issue - "Application Launch Status Request". I'm waiting to hear back from RIM and will update this answer once I do.
UPDATE: Our issue was a simple mistake -- we did not upload all the necessary COD files in our filebundles. However, RIM APPROVED the app and it went into App World! Attempting to download the app crashed App World 3.0 with the message "There is an issue with BlackBerry App World. BlackBerry App World must now close." Ultimately, we received an e-mail from App World support saying they had denied the approved release and we could move it back into draft and upload the complete filebundles.
So yes, you CAN stop an app submission (even after it's approved and up for sale), but only by e-mailing App World support directly. There is currently no way for vendors to do this manually as in iTunes Connect.