Under RTI, as a citizen, one has as a right can seek that information which is available on public record in the form of a material.
You have been raising the legal validity of documents from an officer who is concerned with the registration of those documents after collecting such fee and not concerned with the title of the property. This may be your grievance against Registration or may be questioning his actions on such registration. RTI is not for redressal of grievances and authorities can not be questioned on their actions under RTI.
It is the buyer's option to exercise such prudence and care while investing amounts in landed property.
Contact any local advocate with the facts and it takes less than 10minutes for his to go through such documents and give a valid legal opinion.