Employer not paying salary

Dear Sir/Ma'am Recently I have resigned from a job that I had joined two months back on 24th August. During the interview the lady offered me an amount which was beyond my expectations and it felt lucrative. It was an academic writing firm and it's head office is in Gurgaon. The company's name is LOCUS Rags and the owner is Mr. Ankush Tambe. I was offered with 20,000 INR per month. The offer letter I received after joining included this amount along with the details of the office timings. Later on after joining and working for few days I received the appointment letter where it was mentioned that I need to achieve a certain word count for receiving the full salary. I asked the lady that interviewed me about the target and she replied that the entire salary is target based. It was not communicated earlier and so I felt that the company is misrepresenting facts in order to fool the employees. I decided to quit after getting salary for August. When I told the lady about my decision she said for the first three months the salary will be full irrespective of the target. After 3 months it will be target based. But for the month of August I received only 4600. This again made me raise questions to which she replied that only for 7 days we can't pay you 20000, you will receive the entire amount after one full month. I trusted her but the target seemed unachievable and moreover the concept of target based salary didn't impress me. I told her about it and said that I want to quit. This time she talked to the management and reduced the target a bit for all. So I worked with them for the whole September and at the end of September I found that the target wasn't achieved even though it was reduced. This time I received my full salary but I was worried about the future months. After thinking for a while I decided to resign. I notified her and submitted the resignation on 1st October to which she asked me to submit the reasons for my resignation. I submitted the reasons but didn't get any response. It was written in the appointment letter that I'm bound to serve the notice period after resignation and so I served it. In the meantime I didn't even receive an approval/acknowledgement of the resignation mail sent by me. Throughout October I served my notice period and then when the month ended I didn't receive my salary. As I asked the lady she told me that the works done by me needed improvement. So even after serving notice period is worked on the pending works. I asked her through mail that whether I will get the salary after doing the work. She replied yes. Then she kept on harassing me by reverting back with the same work repeatedly. It was irritating and so I wished to visit the office for further discussions on the work. She refused to allow me to office. Next day I received a call from HR Mr. Hitesh Agarwal. He told me that I need to sign a legal document agreeing to the fact that I will do the pending works for the next 1.5 months. If I agree only then I'll get the salary. I agreed but since then I didn't hear from him. Along with me two other employees got treated the same way and in august another employee left the firm because he was not getting his due salary. If these fraudulent firms keep on exploiting the generation in this way then how will we develop as a whole? I've lost my trust on employers now. They are simply making fun of law and order. I would like to know how can I teach these guys a lesson so that they stop exploiting the employees in future. Please suggest me some less expensive way outs. Regards