I am the regular user of the Carbonite online backup. Once it was hang when i was using it but after that i never got any problem with this service. With mine it is working properly. It may be some problem with the configuration so configure it again retry for backup.
The problem isn't in the backups completing; it's that the backups that complete do not actually include the Espionage-encrypted data. At least that was the case when I used it. I would definitely recommend doing a test restore of some encrypted data to ensure that what you think is being backed up is actually backed up.