Non-payment Of Variable Pay (Annual Variable Compensation) By My Erstwhile Employer

I would like to bring to your notice a concern with regards to the non-payment of variable pay/annual variable compensation by my erstwhile employer. I was employed with my erstwhile employer (IT Sector) located in Pune for a little over a year (from Feb 14, 2019, to Apr 09 2020). I have resigned from duties on 11th January 2020 and got relieved from duties on Apr 09 2020 after serving the mandated notice period of three months. The company pays the variable payout annually along with the March salary. The company withholds the variable pay component for the months Jan thru Dec and is paid along with the March salary in the subsequent year. I have not received the variable pay and I later got to know that as per the company's policy, employees are not eligible for variable pay if serving notice period as on the payment date. As I was in notice period during that time, I did not receive the variable pay. What should I do in this case? Please suggest.