How to seek legal help to get my unpaid salary for the previous month from my company?

I am working with a company for the past three months at Kolkata . Now, my employer is refusing to pay me my salary. The salary payment date is 7th of every month. In this month Dec, 2017 I gave my resignation. However, at 7th Dec, 2017 every employee at my company have received their salary except me. After I spoke with the HR, i was informed that due to a technical failure my salary could not be processed, which was quite surprising, provided that in the previous months, there was no occurences of delay or any technical failure. They further told me that on 17th Dec 2017, the salary would be processed again. I am apprehensive that my company is trying to rip me off as because the company has such previous records of duping employees who plan to quit. I believe that they plan to make me work on without pay for some days and then fire me without giving me my salaried amount. Please now advice me that what should I do to get my month of November 's salary. Please I require urgent help as soon as possible. My email- [deleted]