Sounds like a problem with NEO.
Test. If you can un-tar/un-zip a Moodle backup on a local machine and it un-tars or un-zips without error ... and one has or sees a moodle_backup.xml file in the un-tarrd/un-zipped extraction then Moodle did it's job. Another test ... restore the backup to the Moodle you are using only to a different course or another Moodle instance of same or higher version.
Again, IF Moodle can do that/those, your moodle is functioning as it should ... wouldn't you agree?
Thus, contact NEO support and inquire there.
Good luck!
'spirit of sharing', Ken