Last week, Centrelink tweeted that its offices were closed and people needing help, support or advice should call Lifeline.
Human Services Minister Alan Tudge is still on holidays, leaving Social Services Minister Christian Porter to deal with the fallout.
Opposition human services spokeswoman Linda Burney said the Government had mishandled the matter.
“The Government response to this mess has been abysmal,” Ms Burney said. “It’s time for Minister Tudge to get back to work. A system working well does not force innocent people to call electorate offices in tears.
“If the system was working well Centrelink wouldn’t be telling people on Twitter to call Lifeline.”
Mr Porter has defended the system and said since July it has “raised” almost $300 million in overpayments.
But The Courier-Mail has learned that figure is the amount of debt identified, rather than repaid.