When Canberra pensioner Barry Cole received a phone call in May 2017 telling him he owed the government $21,000, he thought it was a scam.
"I'd heard warnings about these people ringing up and saying they're from the taxation department and all that sort of thing," Mr Cole said.
When a second call came through saying he'd soon get a bill in the mail, he began to worry.
"When I did get a letter, I received it on the 31st of May 2017, I got this bill for $21,083.99. They had to get the 99 cents," Mr Cole said.
He later received a second bill for around $100, bizarrely dated back to 1963 when he was 28 years old and working in the family company.
Unable to get any answers through the Centrelink shopfront, he paid the bills.
The 85-year-old is one of more than 400,000 Australians who were a part of the robodebt class action, who are now waiting to find out if and when they will get their money back after the landmark $1.2 billion settlement last week.
Services Australia disputes that Mr Cole should have been part of the class action.
A spokeswoman said Mr Cole's main debt was raised as a result of an income stream review relating to his superannuation income which was not part of the class action and he was not issued with an opt-out notice.
However Gordon Legal maintains Mr Cole was eligible for the class action through his second $100 debt.
Mr Cole was uncertain if he would get money back but was left confused by the way Centrelink handled his debts.
"I went down to Centrelink and no answers, no nothing," Mr Cole said.
He also still has questions about how the scandal unfolded.
"Someone needs a kick in the bum about the whole thing," Mr Cole said.
What Mr Cole did not know at the time he received his $100 bill was the legality of the scheme had already been questioned by Administrative Appeals Tribunal member Terry Carney in two separate cases.
Every day that no minister is stood down over this theft from the public is another argument for a robodebt royal commission as the only route to accountability.Labor government services spokesman Bill Shorten
Labor's government services spokesman Bill Shorten said it was "extremely offensive to the Australian public that no one in this government is taking real responsibility for this $1.2 billion scam".
"Every day that no minister is stood down over this theft from the public is another argument for a robodebt royal commission as the only route to accountability," Mr Shorten said.
A spokesman for Government Services Minister Stuart Robert did not respond to questions about whether the government had commissioned an internal review of the robodebt failures.
Instead he pointed to previous statements from Mr Roberts, where he said, "the Commonwealth's agreement to settle the matter is not an admission of liability by the Commonwealth, and does not reflect any acceptance by the Commonwealth of the allegations that the Commonwealth, or any of its officers, had any knowledge of unlawfulness associated with the income compliance program".
The government has already repaid $705.9 million to 405,814 people - around 95 per cent of people owed a refund - separate to the class action.