This year on April 29 Estonian investors of Arricano Real Estate Plc, the leading developer of shopping malls in Ukraine, sent a Notice of Investment Dispute to President of Ukraine Volodymyr Zelenskyy and the Ministry of Justice of Ukraine demanding compensation of USD 750 million.  
The report claims that the Ukrainian authorities expropriated their investments, which were aimed at the development of the Sky Mall shopping center, in favor of third parties. They also violated other rights stipulated by the Agreement between the Government of Ukraine and the Government of the Republic of Estonia on Promotion and Mutual Protection of Investments of February 1995. But investment activities in Ukraine were followed by a campaign of intimidation, pressure and abuse of official duties by the law enforcement agencies of Ukraine. 
After the Notice of Investment Dispute is submitted, a six-month pre-arbitration settlement period begins, during which the parties will be able to reach an agreement. 
If the parties fail to do that, investors will submit a notice to the Ukrainian government to apply to the international investment arbitration against Ukraine and the dispute will go to court.  
According to the Article 8 of the mentioned intergovernmental agreement, any dispute must be the subject of negotiations between the parties. In case of unsuccessful settlement of the dispute within six months, investors shall have the right to refer the dispute to the international investment court - the International Centre for Settlement of Investment Disputes (ICSID) or the international tribunal "ad hoc" under the "Rules of Arbitration" of the United Nations Commission on International Trade Law (UNCITRAL).
Source: https://www.londonstockexchange.com/news-article/ARO/update-on-sky-mall/14964366