It's the latest blow to Tongasat, a private company Prime Minister 'Akilisi Pohiva has accused a royal princess of using to take millions in public money.
Tongasat had launched an appeal over a Supreme Court decision from August last year, when the Supreme Court ruled $US50 million in payments China made to Tongasat was grant aid intended for Tonga's government.
The company wanted fresh evidence to be heard from four key witnesses, including former finance ministers Lord Matoto and Sunia Fili and former Department of Finance officials 'Aisake Eke and 'Aholotu Palu.