Non Payment Of Salary.

We(57 person) are engaged in a power plant in Orissa through a manpower agency from Delhi i.e., third party employees or off role employees. From November 2016 we are not getting any salary till date. When we are asking for the same, the agency is saying that the principal employer is not making the payment and when we asked the principal employer they are saying that they don't have any fund to clear our salaries. Kindly suggest what should we do. N.B.- We are not provided with any appointment letter or offer letter or salary slips nothing. Just a ID card.