Issuance of full and final settlement even after 45 days.

I was working with a okhla, delhi based bpo in technical support. I joined them at agent level and due to performance i was promoted as a supervisor/ Subject matter expert. They never issued a offer letter, i kept asking for it. I worked there starting from august 2014 till june 2015, in between they issued me a promotion letter for above mentioned post. i was even taking interviews of new candidates for this company for which i have recordings and text or what's app messages from managers and team lead. on june 19th one of company director was on floor and he asked me to do a customers heat check in which we ask customers that how he liked the service and whether he is satisfied or not. which took some time as customer was busy checking his computer. Due to the delay director lost his cool and shouted on me and on one other agent and asked us to follow him in his room where he tried to even hit me but then stopped and told me to forget the salary. However my manager handed me my salary check for previous month. They didn't give any termination letter and on asking for it they said that if they see me in near vicinity then it won't be good for me. But my manager assured me that he will get me every thing later. I trusted him and asked for full and final after 45 days which they all refused, manager and even director. i have the call recordings of all too as my phone records every call automatically bcoz of an application. I think i should get 2 months salary as they terminated me and also the amount that was left and compensation for delay. Suggest me if i can take any action. I am only worried because they didn't give me any paper for the job.