Gpa

When a principal of a GPA is expired the GPA given by him is automatically cancelled and GPA agent has no right to execute deeds on befalf of the pricipal.  

But at the same time of GPA registration, a unregistered note referring to the GPA, is prepared as below:

A consideration of Rs. 50000 is paid in exchange of the immovable property and the property is given right to sell the land in plots,; It is so mentioned that the GPA is irrevocable under any circumstances. 

The principal died in 2001 where the GPA was registered in 1999.

The agency has sold the plots from 2002 to 2016 (13 registered sales) i.e. after the death of the principal. The agency while registering the sale has mentioned that the GPA is active and the principal is alive.

Please clarify whether (1) the  unregistered note, (mentioned above) is valid and irrevocable and (2) whether the agency's 

statement thar the pricipal is alive at the time of registration (i.e. during 2002 to 2016) is legally tenable.

What would be the course of action.?.