What legal steps can be taken, if you have been terminated illegally?

On July 29th, I resigned n requested a possible release within 20 days(by Aug 19), knowing recovery might apply if I didn't serve the full notice period. I was on the bench, I expected HR to discuss the recovery, n I was willing to serve the full notice period if needed. Instead, the company released me in 5 days without any discussion, which raised concerns. HR later informed me that my leave balance and 8 extra days worked would cover the ₹1.7 lakh recovery. They didn't notify me in advance that August 2nd would be my last working day; I found out at 5 PM that day. I immediately emailed HR stating I was ready to serve the full notice period if recovery applied but got no response. They now claim that since I requested an early release, the recovery stands. I have proof of these events and am worried about my pending full and final settlement. Despite being a top performer, I feel unfairly treated. I'm awaiting official Full and Final confirmation and have 30-40 days to consider my options.