But it is alleged that days later, Barfoot agent Ricky Yap, who handled the sale and rejects claims of any wrongdoing, received a text message in Vietnamese from the vendors which read: "Hi Ricky, I don't want to sell my house any more. Please cancel."
Details of the case were outlined yesterday in the High Court at Auckland before Justice Rebecca Edwards as the out-of-pocket purchasers opened proceedings nearly two years after supposedly buying the house.
Their loaned deposit remains in a trust account while the case is settled and they say they have lost tens of thousands of dollars in rental income and interest payments as a result of the stymied sale.
The court heard the couple own a number of rental properties, including the neighbouring Church St house.
When the nextdoor property came on the market they decided to buy the old railway cottage and renovate it, making a pre-purchase offer of $440,000.
The court heard the offer was accepted and the auction brought forward, where they bid another $10,000 to clinch the house.
"I did everything that was asked of me to complete the agreement," Mr Piner told the court yesterday.
"Barfoot was in control of the arrangement and I relied on them.
"As far as I was concerned I had bought the property."
Mr Piner said that after the auction he thanked the vendors and shook hands. "They seemed pleased."
But days later it emerged the siblings had "changed their minds about selling", he said.
"They had decided not to sell but did not give any reason."
Mr Piner said the couple put a caveat on the property and their lawyer wrote to Mr and Ms Nguyen but received no response.
As the settlement date came and went, the couple delivered a translated letter to the house where Ms Nguyen was still living.
"We still didn't get a response so we issued these proceedings."
Mr Piner said the couple wanted the court to enforce the sale agreement so they could finally take possession of their investment property.
Barfoot is named as second defendant in the proceedings. Barfoot's lawyer Tim Rea said the realty firm had "no factual dispute" with Dr Glover and Mr Piner's version of events.
It believed the couple had an enforceable contract. "When you've heard all the evidence it will be fairly persuasive that there is in fact a contract formed."
The defence is due to give its opening submissions today.