In addition, I suggest that you can negotiate with the intermediary to sign a supplementary agreement, requiring the owner to complete the bridge crossing before a certain time, otherwise it will be treated as a breach of contract and the amount of liquidated damages will be agreed. You can collect liquidated damages according to the contract if it is not completed, and you can buy a house normally after completion. Of course, if you really don't want to buy this house, just refund the deposit directly, and the compensation part is open to question.