Poa

Sirs, In 1991 a land was sold to Group hosing soceity thro POA. But the POA was not registered. The housing soceity has been formed and this particular site has been mentioned as Civic Aminity site. Lateron, in 2006 the property was sold through normal sale deed by the owner to us. Now the court says that it being the CA site it has to be cleared immediately However this site has "A" Khata and an appartment wass construted and around 40 families are already living now. Now, 1. whether the non-regitered POA can be considered as legal sale and the site would be considered as CA site or 2. As POA is not registered it is invalid and the property lateron sold & registered on 2006 will be considered as legal transfer and it cannot be considered CA site. it may be noted that the original owner who executed POA in 1991 and sale deed to other party in 2006 is not alive now. 3.As the person is not alive now and POA is not registered at any time, the POA becomes invalid on his death? Please advice