My question is not a simple one. I'm currently unemployed…

My question is not a simple one. I'm currently unemployed and my question deals with Centrekink. In October the Centrelink Self service system had a fault in it and I could not log into their report income section and had to go to Centrelink to report and the staff had to input my income into the Centrelink data base computer system. I gave them the information, Employer, dates and hours worked and pay rate and they inputted this into the system and informed on how much I would receive for the fortnight. The following fortnight I had to repeat the process again as the fault in their system was still apparent. I again gave them the relevant work information and they logged it into the Centrelink data system and again informed me of how much I would receive in benefits. Several days later I received an e-letter from Centrelink stating that I had been over-paid and would have to repay the money. I rang their claims department to find out how this was possible as it was the Centrelink staff who put the work information into the computer system and not myself. I was informed that work and pay details were input incorrectly leading to the over-payment. As I stated to the claims officer that seeing as it was a staff member who was responsible for the error it should be them that is made to make repayment as it was their error and not mine so I appealed their decision. But they have since sent me a letter stating that my appeal was unsuccessful and that their rules and regulations state that I'm responsible for any oversight and repayment. I do not argue with the fact that was overpaid. My argument is that the error/fault was not caused by me but by their staff and I am being penalized because they made the mistake and get off free of any wrong doing.
I know trying to take on Centrelink over this matter would be a waste of time because of the Federal Government backing. But my question is, "Can I take legal action against the staff member responsible for the error and the Management of the Woodridge Centrelink for not ensuring their staff are properly trained? I know for a fact that I am not the only one who has had this happen to them and the staff are not penalized for their inerrant actions.