He was among almost 170,000 people who received a bill from Centrelink as the government body struggles with its new automated system.

Criticism has been harsh across the country, with many people receiving a letter for debts they knew nothing about.

Mr Simpson’s bill was for $7831.66 and he was given a month to find the money and pay.

“It was for the full amount of the Family Tax Benefit paid to me from July 2014 to June 2015,” he said.

“I was shocked, I thought how am I going to come up with that money.”

The letter stated that he or his wife had not lodged their income tax returns, but Mr Simpson said they both had.

Even after spending almost two hours on the phone to Centrelink, and being told by the operator they had made an error, he said he was still advised to begin paying the bill off to avoid it going to the debt collectors.

“I’m happy to play by the rules, but if you’re going to send out letters like this they need to get their fact right,” Mr Simpson said.

Since the national debacle became public, the government has scrambled to defend Centrelink’s recently-introduced automated systems, and federal social services Minister Christian Porter told Fairfax Media that it was working well and the complaint rate was running at just 0.16 per cent.

“An internal Centrelink check is said to have found that only 20 out of hundreds of cases reviewed are genuine debts,” Fairfax Media recently reported.

Mr Simpson said while he was savvy enough to realise that the bill was incorrect, he feared other people may simply pay it.

“If my bill was only $1000 I might have just paid it and not questioned it,” he said.

Mr Simpson said he has since been provided with a revised bill of just under $1000, but said he has not paid it fearing that it too is incorrect.