Copyrights? I can tell you if Sidus tried to file legal suit on intellectual property rights, they are doomed to loose the case. The regulation on IP is still very weak in Japan and Korea.

Try "fraudulent practices" may stand a chance. Contact the Korea Independent Commission Against Corruption (KICAC) for this matter. Apart from corrupt practices, KICAC also looks into fraudulent practices.

For Japan side, contact the Freedom of Information Citizen Center.