Maldives Gets $800 million New Airport Island For Nothing After New Dictator Declares Infrastructure Charge Illeagal

Ok you are a small island state and wish to build a new airport which requires reclamation of a new island, the largest infrastructure project in the nations history.  You give the contract to a Malaysian country company that in return gets a concession of 25 years and in the contract the right to charge each departing  passenger an infrastructure fee (25 dollars) to pay for the capital cost.

This is massively unpopular and the government leader that signed the contract gets overthrown in a coup.  The incoming leader gets his crony judges to declare the charge illeagal.

The result GMR of Malaysia are $800 million dollars out of pocket.  They say they will sue, in which courts where?