@lahm-44 @ vileygroun @noel57 , his problems are sorted out , hope u didnt read everything

i am quoting that for you guys , OP has to edit his first post and inform about how he solved his problem too
Just to let any Internet searcher know the end of the story. I filed the case with Australia Ombudsman Service. They asked the bank to reach a resolution with customer themselves, with a deadline attached (tomorrow) and the bank complied, solving the case to my expectation. So there are no financial loses except the uneasiness.
So, this time, the victim, whose account is hijacked to pay for Bitcoin purchased from me, lost. I didn't lose nor win. The hacker won.
Lessons learned:
1) for the victim: watch your bank account balance.
2) for bitcoin seller: if buyer is buying piecemeal, they maybe a criminal, hoping the victim didn't notice their bank balance changing. Ask for more ID proof. I do have regulars, but they don't buy fix amount, and I know them in person.
3) do not accept bank transfer because the banks can reverse them. Although you can get them back, like I did, its not worth the effort.