Ancestral property dispute

If A,B are brothers and their father was original owner of a property and after his death it was transferred to their mother and after her death it was transferred to A alone without any registered release deed of B and society recognizes only A as a member and is not cooperating with B in any way. So now in order to safeguard his legal rights in said property B has taken possession of the said property and was paying the maintenance for 2 years. But, when B demanded a simple NOC from society, it has denied to issue it to B saying that it doesn't recognize B as a member instead of knowing that B has been cheated and the property is transferred to A alone without the agreement with B and society is not replying to emails of B questioning about documents by which it was transferred to A. B maintains that B would pay maintenance when property is transferred to him. A is pressuring B to pay it. What should B do?