Joining got postponed

Hi, I was offered a job in Company X with joining date of May 4, 2020 so I have resigned my existing job. But suddenly HR told me that due to COVID situation we are unable to onboard you at this time but once lockdown is lifted then we will be on boarding and they did not give any specific date. But later after I made multiple follow ups they told that the job is put on hold for specific department that they hired me initially and they will arrange for an interview in another process. As said they arranged for one more interview and said they are waiting for final approval from COO, again they called me and said they did Not get approval and now arranged for one more interview which the said I got rejected and they will look for some other department. So as they offered me a job initially and I have accepted too, now as they are deferring the joining with no specific date, can I a file a case against company as I already lost my salary already from May to till date Aug 20 and it still continues as they dint give me any date yet. I would be glad if you could provide me a solution on how to proceed under this situation.