Termination without paying the wages

Dear Sir/Madam, I have been working in our company since March 2016. I have given my heart and soul to establish the company, however, we employees always faced irregularities in payment. Since August 2017, they started to hold 2 months salary and on the next month, they pay the salary of only one month. This way we always had 2 months dues hold by the company. But currently, they have not paid the salary for the month of October 2017, November 2017, December 2017 by giving the reason that company in the loss.But when it comes to work, they always pressurize us and also give threat that they will not pay the salary. Also behave very badly with the employees. This is why I went office and asked for the salary on last week, and I said that we all have to pay our liabilities, so nonpayment of salaries for the last three months is not good. In reply, they said that we are nobody to decide when the company will release the payment. I had the conversation with the management for half an hour on that day and in return, in the evening they have mailed me the termination letter for the behavioral issue which is arbitrary and false as the salary is our fundamental right for which we work there and we can ask for the same, as it's our legal demand. They have taken all vague and unethical grounds to terminate me. For your reference, I would also like to inform you that, on 1st July 2017, they have given a sheet of paper mentioning, in case of loss, the company will deduct some amount from the salary of its employees. When we denied signing the paper as this has not been told at the time of employment, they again started threatening us that without signing nobody will get the salary. This way forcefully they made us sign it as we all need money to live for which we are working. They also use this agreement as a weapon to terminate anyone and simultaneously on the pretext of that agreement letter they do not pay the salary the legal dues of the employees on time. Also, when the employees demand the salary they usually start finding unethical grounds to discontinue their employment by holding their previous dues (salary). I will be very much obliged if you please suggest how to proceed legally and is there any online portal of Indian govt. to lodge complaint like this.?