The Block winners Jimmy and Tam Wilkins have lost their $1million prize and have been forced to put their home back on the market after its buyer failed to pay up.
Cyber security specialist Emese Fajk, 28, was the mystery buyer who snapped up Jimmy and Tam's winning property on The Block last month.
Ms Fajk presented receipts of bank transfers indicating the money for the home had gone through, but the large sum never reached Channel Nine's bank accounts.
The settlement period for the Brighton property, which fetched $4.256 million on auction day at a profit of $966,000, has now passed and the original contract is void.