Does anyone know of a way to unlock an ipad that is locked with the activation lock whereas the activation lock bypass code that you get from within the JSS under management does not work. Is there any other way to unlock the ipad except to call Apple and show proof of ownership.
The first and easiest route is if you happen to know who had the iPad and maybe they'd be willing to type their password to unlock the device.
Otherwise, I think you're stuck with contacting Apple. If you've got enterprise apple support, they provide a generic spreadsheet that you fill out and email to a contact, usually turn it around within 24 hours. We utilized this when we sold off older iPad 2s that had to be unlocked for the purchaser.
If the iPads are in your DEP, that's proof that you own it.