No Full And Final Settlement Paid After 20 Months Since Last Working Day

My past employer has not paid me my Full and Final Settlement which includes salary for a month and a half and it has been more than 20 months since I left the company. I had served my notice period and according to the company policy, the settlement is supposed to be done within 45 days from the last working day. I had sent out a couple of emails to my employer and the management, to which they hardly replied. I even tried calling my employer who did not answer my call. The last email from the management in January had stated that they are in a crisis and will need some time to clear the dues. And now they aren't replying to my emails and turns out the company name and address have been changed and after my last email, the previous company email account has been shut down. Could someone please help me what should I do now? I have given them enough time to recover from the crisis and the COVID impact. But they have only taken advantage of it.