What should i do if employer refused to pay my stipend ?

I am a college student of Jamia Millia Islamia , New Delhi. I was intern at a private firm Akkidokie Digital (27/21 East Patel Nagar, New Delhi 110008) for about one month (from 25th of July to 1st of September excluding leaves of 5 days). After which I left the organization due to the fact that I was not able to cope-up with my studies also I was not happy with the work that I was supposed to do in the firm and coincidentally the were also not somewhat fully satisfied with my work. Hence I left the organization on 1st of September after completing that day’s work. Before leaving the manager said that she would release my stipend as soon as the stipend of my fellow interns would be released. After two weeks my fellow interns received the stipend and when I tried to contact them they were being unresponsive. They finally responded through e-mail when I sent application through registered post in the name of the manager demanding my due stipend. When they responded they issued a termination letter in my name (which was backdated to 31st of August and sent to me on 22nd of September) and refused to pay my stipend on grounds of misbehaviour and very poor performance which is completely false and neither was told to me earlier in my working days. No such letter was given to me on 31st of August and neither on 1st of September. Also since they were quite smart in responding they also wrote in termination letter that " During your time with Akkidokie Digital, you have failed to meet every performance and behavioural measure. After 1 week of employment , you were offered additional coaching which you turned down." I was never told about my performance until the last day when I left i.e. 1st of sept 16 and never had any behavioural issue with the company.They also never gave me any training after one week which they are saying , all the interns who were my fellow mates, we were never given any kind of training. Also as much as i know or as much as i have read online you cannot remove an employee without prior warning about his performance and even if he has a poor performance firm should make measures and provide a training for improving his/her performance. So all in all they have written this so that i cannot blame them In future but it is completely false. Instead even if we have to talk about behaviour ( of my manager ) she used to talk to us in slang language many a times which I and my fellow interns ignored most of the times. So I think behavioural issue is with them instead of it being with me. Now since they have refused to pay my stipend and quite a time, work and money have already been put up by me in going to the office. I request you to kindly advice me that what should i do now. Please reply as soon as possible. Thanks in advance. Regards Punit K. Pal Any help would be sincerely appreciated.