Government rights to transfer land

Person A Sold Land to my having government rights to transfer hence I stated taking permissions. Know B is asking money based on registration year 1992 with A . When I check A and B while registration they had hidden information about government rights to transfer, 50% Najarana , sale permission requirement also 7/12 not attached with Registering. It is like normal land transfer shown in registration hence registration approved. But when they tried to transfer land revenue department rejected in mutation entry. So Land remain on name A My quarry is 1)Should B is legal and I should pay him 2) Can B regularize his registration if I had not pay amount to him .3) B is saying he not knowing rules in year 1992 for this land is ground get acceptable & In year 1992 there is not hard rules 4) Can registration office reject after knowing this present year.