Since the weekend all ATO systems have been offline as the ATO suffers a "World First" system failure for a government tax authority. Apparently the hardware supplied and supported by Hewlett Packard has crashed as well as their backup systems.
So effectively the ATO at the moment are deadline in the water and unable to process any returns or refunds until they get there systems back online. When will that be, no one can really say at this point in time.
This is a timely reminder to make sure your own backups are in working order.