If your life is in danger, call the police at 110

Rodokijun Kantokusho (Labor Standards Inspection Office)

There is an office in each district (no English except at Tokyo, where caller needs to ask for “tsuyaku”), you should have a documented problem with employer, i.e., violation of contract. You should also contact Immigration authorities at the Ministry of Justice. Tokyo: 03-3814-5311 Kanagawa: 045-211-7350 Chiba: 043-221-43111,