Unjustified Termination without reason

Dear Experts,

I have been terminated from service with immediate effect.
But there is no reason mentioned in the letter.
I was on probation in a limited company.

In my appointment letter termination is in cases of misconduct. I was having good conduct and regular in office.Also I was never asked or told about any misconduct, if any, by my seniors before terminating me.

Before termination, my reporting manager had forced me to resign.he did not tell the reason. I thought it is due to performance.So I said I am ready to perform and I'll work, I dont want to resign.He didnt listen, and in a week's time he gave me termination letter with immediate effect.

I asked management in 3 written format,for the 'reason' of termination. But NO CLEAR reason is given .'Performance' is UNCLEAR reason forwarded. But in my appointment letter, termination on low performance is not mentioned at all.

I feel that termination of my service was injustice done to me when I was ready to work hard and perform.
I have a good career record with 2 promotions in my previous company.My branch manager has no right to ruin anybody's hard earned career due to his politics.
I was victimised by my branch manager. He has a habbit to torture employees on probation and make them leave job themselves in frustation.

My manager is also telling some 'misconduct' reasons about me to management AT MY BACK.
I am following up with 10 emails sent uptill now to HR and till chairperson of company asking for justice, but management is not responding positive.

I want to fight against this injustice.
Please guide me, could I take up this matter legally?

Thankyou,
With Best Regards