Salary Issue with with Mental Harassment

Hi, I am talking about one start up company based on Hyderabad. Before one year I joined here. Company also provide me the appointment letter. Their everything is mentioned. But now the problem is that, they want to close the company without FNF sattlement. Even they didn't maintain their words as per the appointment letter. Now they are also giving me a lot of mental pressure. Even I worked till date, they didn't even clear past 3 month salary also. I have each and every documents in my own mail. This is not first time. After taking some information, I got to know that they did the same thing with the previous team also. Will you please suggest me what I have to do now to get my old salary and FNF sattlement.