My grandfather took a land on rent to run a workshop about 30 years back from Ram. After few years(likely 7-8yrs)Ram offered my grandfather to buy the land and my grandfather agreed and paid some amount to Ram but not the full amount. Coincidentally due to illness n age factors Ram passed away without any registry or agreement legally but left a note of amount taken from my grandson against the land. RAM had 1SON and 5 DAUGHTER'S and his Wife was also alive. Ram's son refused to sell the land n took my grandfather to court, but later settled the matter and sold us the land. The registry finally was worked in year JAN 1991, in which the Ram's son KARAN wrote that, "i the only son of my father agrees to sell the land to _____". The registry was on the name of my father as per my grandfather's wish (my grandfather is still alive).My father passed away in 2006 with no will, and the only legal heirs of my fathers property are my mother, me and my minor sister. Now we want to sell the land but the buyer's lawyer raised the issue that the registry should be signed by Ram's daughter i.e karan's sisters. Is the point raised by the lawyer is correct, if so why..?? what can i do now. There is no hope that i can get it signed from all five sister's of karan now.I have not received any notice from anyone related to the ram's family since 20 years from registry. Is there any kind of time barred law? please help on this topic