Employer not clearing dues even after 90 days of exit

I had left my employer after serving the notice period on 03-12-2016. I was not paid the salary for Nov'16 when I left and now with over 90 days lapsed for payment of FnF, they are making excuses and delaying the FnF on some pretext or the other(stating that the payment shall be released once they get the payment from client, whereas client has released significant amount and held the balance as they had not paid the client for the services taken from the client). How do I go about the same