When Clare Wainwright checked her bank account on Thursday, she did not expect to find herself $24.5 million richer and her mortgage paid off.
Ms Wainwright said she felt "quite great actually" when she saw $25.1 million had been transferred to her account at the National Australia Bank.
"I'm a lawyer, which is why I haven't spent the money," she said. "Mostly because I figured it wouldn't play out that well trying to play dumb on that."
Yet Ms Wainwright's efforts to alert the NAB to the mistake appear to have been ignored.
The saga of Ms Wainwright's unexpected riches began in September when NAB sent a letter confirming a direct debit for loan repayments had been set up.
The letter stated Ms Wainwright's monthly repayments would be $25,102,107 - not $2500 - with the next repayment due on October 25.
"I saw it and I thought 'Oh my gosh, it's 25 mil' and I laughed," she said. "I showed my broker and he said 'Oh god, I'll get them to fix it'."
But the bank did not rectify the mistake.
Ms Wainwright said NAB appeared to have requested $25.1 million from her account at St George Bank, which transferred the money on October 25 without a second thought as to why their customer was dramatically overdrawn on her account.
"Both banks have messed up," she said.
Ms Wainwright asked her mortgage broker to contact NAB again. Their response? "Someone will be in contact with me within three business days about my query," she said. "So they obviously don't understand I could just skip the country."
Ms Wainwright said the bank finally contacted her mortgage broker on Thursday night, but the money remains in her account.
"It's still literally just sitting there," she said. "I've just checked my account."
An NAB spokeswoman said the mistake had been rectified and an investigation into the cause was underway.
"The error has been fixed and the payment has been reversed," she said.
"We are looking into how it occurred."
St George Bank has been contacted for comment.
Ms Wainwright is not the first bank customer to find untold wealth in an account. Fairfax Media reported in 2016 that chemical engineering student Christine Jia Xin Lee spent millions of dollars on handbags and luxury goods after Westpac gave her $4.6 million overdraft by mistake.
Melbourne man Matthew Pearce had $123 million mistaken put in his Commonwealth Bank account, according to The Telegraph.
"You should not spend or withdraw the money transferred into your account by mistake because it is not legally yours and you have to pay it back," according to the Financial Ombudsman Service Australia.
Asked how she would spend $25 million, Ms Wainwright said: "Well, if I was allowed to use it, I'd pay off my mortgage and buy another place. Or an island."