How to deal with illegal termination and maternity leave issue

I am 7 months pregnant lady. My manager has initially forced me to resign when I enquired for the maternity leave and when I denied to resign, she terminated me saying that I am a poor performer. When I requested the higher authority regarding my termination issue and harassment by my manager, he said my termination is final. They are also blaming me that being a pregnant woman, I want to take the advantage of new maternity act. So finally I decided to fight to get the justice. So far, I have sent one legal notice to my employer but no response yet. Please advise me for the next steps. It would be a great help for me. Thanks!