Wuhai Chemical Co., Ltd. didn't pay for 8 months.

You can complain to the labor inspection department.

According to the Labor Law of People's Republic of China (PRC), the employing unit shall pay the workers' wages in full and on time as agreed in the labor contract. If Wuhai Chemical Company has not paid wages for 8 months in a row, this obviously violates the provisions of the Labor Law. Laborers have the right to demand the employer to pay the arrears of wages, and they can complain to the labor inspection department.