The PoA might have to be attested by Indian Embassy/consulate
Or notarization was sufficient for the purpose of PoA
and if the PoA was to be adjudicated/registered locally in India..at location of property/agent..
Check locally which and where is adjudication office/who is adjudication officer SRO/Distt.Registrar/Collector of stamps/SDM etc etc …..as per state rules….
As per reply given to you IT seems that adjudication was not required at the time when agent acted by PoA…
Or the act by agent was erroneous..
At the time of act of registration the POA has to be (re)presented with agreement for sale deed….
So the copy should be available..
Discuss with LOCAL senior counsels of unshakable repute and integrity specializing in revenue/civil/property matters and well versed with latest citations, LOCAL applicable year wise rules/laws/ … and having successful track record…. and worth his/her salt…..and show the case related docs etc etc ..for support and help..
Even senior deedwriters may be able to help you on the prevailing rules as on date of act by agent.
You may also check if the state govt website provides detailed information or FAQ e.g;