Forced Resignation Without Releasing The Salary

i am working in a private BPO as manager level since last 18 months (I have a team of 45 peoples under me). now company informed us as process getting ramped down and asked us all to leave the job(Last working day would be 27 th Oct 2016). means 12 days before intimation(Not given any written confirmation). today is 15th Oct and we yet not got salary of sep'16 (salary date is 10 to 15 every month). we are continuously asking to HR but they are saying we cant to anything.
MY QUESTIONS ARE BELOW.
if we will not get last month salary then what should we have to do?
in this scenario, company needs to give a Compensation but why ther are asking to leave?
as per them Oct month salary will be release after 45-60 days as FNF, why we suffer?
request you to please suggest the further actions.

Do you have appointment letter or any other proof of your employment?

yes i have appointment,confirmation & last appraisal letter with me

Donot submit resignation. If salary is not paid than make a complaint to Labour officer in Labour dept and social security officer in PF dept, requesting them to get pending wages and PF contribution from employer. Pl ask social security officer in PF dept to verify your salary details and employment status as on date through monthly reports submitted by employer. This can also be done on their web portal too.