They were found guilty by Justice Tracey Walker of failing to keep adequate records for and report 311 suspicious transactions totalling about $53 million between April 2015 and May 2016.
The Crown case was that Gong was using used New Zealand to launder proceeds from a huge, illegal Chinese pyramid scheme.
Jiaxin Finance Ltd, which is now in liquidation, was fined $2.25 million. Lily Che was fined $202,000 and Michael Fu $180,000.
They appealed against their convictions and sentence to the Court of Appeal, where their barrister, Ron Mansfield, KC, argued that they had no knowledge that Gong was involved in any unlawful activity.
That appeal was dismissed, but they then sought leave to appeal to the Supreme Court.
The Supreme Court has now declined the application, saying that the criteria for such an appeal has not been met.
Last year, Edward Gong cut a deal with the New Zealand Police under which he surrendered more than $70 million in New Zealand assets, including a $2m Auckland house, rather than have the matter taken through the courts.
Those assets had been restrained under the Criminal Proceeds Recovery Act, through which police can seize assets associated with significant criminal activity, and have them forfeited to the Crown.