There is a known issue (but not widely publicised!) that if you delete
your email on your BB10 device it will delete the message in GroupWise
AND the deleted message does not go to trash!

AND!! it has also been known to delete emails for the last 30 days (if
you have 30 days as the live sync on your activeSync server)but you only
meant to delete one email!!

Here is the RIM KnowledgeBase article

"Email messages deleted from the BlackBerry 10 smartphone are not moved
to a Trash or Deleted Items folder and instead are permanently removed"