Getting threatened on Phone

I am PhD student (female) at National Institute of Technology. I had lodged an official complaint against my PhD advisor as she harassed me to do work while I was hospitalized due to pregnancy related complications, despite knowing that I was hospitalized. During maternity leave, a senior of mine called me up and relayed the message from PhD advisor that either I fall in line, withdraw the complaint or leave PhD. I double checked and asked again if PhD advisor really said such a thing and I was told that she directly asked to relay this message to me. I have recorded this call audio apart from all other call audio of conversations (including hospital) with advisor. A year later, the official solution from Dean to my complaint was that there would be no interaction whatsoever between myself and my PhD advisor without the physical presence of HOD. Now HOD is an extremely risk averse person and a yes man. Advisor is taking advantage and not responding to mail (in which HOD is cc ed). If this continues I want to take legal recourse. What is the strength of my case if I file a case against the PhD advisor. I was intimidated through a third party (ex student) during maternity leave who confirms on the call that it is the advisor who wanted to relay the message, and I have a recording of that. Will that strengthen my case if I take this to court?