In a four-to-one majority decision, the Supreme Court backed a group, including Mr Kumar, over their investment in Bowen View apartments on Queenstown Hill's Edgar St and awarded $25,000 costs.
The decision overturned a Court of Appeal judgement which found in favour of developer Station Properties, which was associated with former high-flyer Dan McEwan.
In 2005 and 2006, the investors sunk $72,000 each into Bowen View but refused to settle their under-writing contracts when the apartments' value dropped in the property market downturn.
Station Properties sued for damages and breach of contract.
The case centred on Station's promise to provide furniture for the units and a management arrangement.
The Supreme Court decision said these were ''essential terms'' and the investors were entitled to cancel their contracts.
''In these circumstances, Station has no claim against them.''
In his dissenting opinion, Justice William Young said: ''I am far from convinced that Station was under an obligation to provide a management agreement.''
Bowen View was backed by the Bank of Scotland International (BOSI), which, in 2009, called in receivers on Nigel McKenna's billion-dollar hotel and resort complex, Kawarau Falls Station, now the site of the Hilton Hotel.
When Station Properties collapsed in April 2009, it owed BOSI $20.25 million, Dominion Finance Group $3.9 million and Inland Revenue $1.6 million.
McEwan, who was bankrupted in February 2009 and discharged in March 2012, was a prominent name in the mid-2000s property boom and was behind several high-profile Queenstown developments, including a $60 million proposal to build a Hilton Hotel along Frankton Rd.
