by Ken Task.
First, it's really important to get cron job running. Might be priority #1.
Second, check recyclebin settings - set them to shortest time to retain ... which I think is one second. That hurries along a deletion from the recyclebin state to trashbin. Would also set recyclebin to show in the course menu all the time.
After you finish cleaning up or regaining needed space, consider resetting recyclebin time to retain to something sane - or never make a 'boo-boo' decision on deleting anything!
'SoS', Ken