After my fathers death without will leaving behind the legal heirs Myself my wife, my Mother and Two sisters who are married. But my both sister and their husband has signed relinquish deed at the registrar's office. But now one of my sister and her husband has File Civil Suit before appropriate civil Court for cancellation of entire Deed saying I have misguided them.
How valid and storng is their civil suit for cancellation of Deed?
Can they cancel Deed by filing Civil suit in court?