I am fired from the company on not clearing an assessment

I was hired by a convergys three weeks ago. They did not inform me before joining that in training there will be a assesment that u have to clear and i resigned from my previos company. At the day of joining, they made me sign in offer letter where it was mentioned that they can ask to leave if the trainig is not cleared. As i had already left my previous company so i do not have any other option but to join. My communication trainer said that i was a bottom performer and the management ask to leave. But this is not true because my trainer i felt my trainer was partial with other people in training. He was always passing personal comment on me regarding my boyfriend. He has nothing to do with performance. He used to ask me why dont u have breaks (lunch) with us ( other trainee us to be like always around him). I refused to join him because i need my personal space. Other trainee used to party with him on the weekend but i dont. I already had 2 yrs of exp. in MNC how can be comms skill so bad that u can fire me. Even few trainee like me who dont mingle feel that he was partial and had done the complain to the HR. But no action was taken. Now my question is : How can i raise complain against this? Also i relocated for this and i have not got my first salary. Should i ask for 2 months salary in advance bc i had no job right now. Is it legally right to ask for the advance salary.