Power of attorney doubts?

My mother and myself signed POA infavour of my father without reading the contents since we belived him some 8 years back. We don't have the copy of the POA. And we don't have our properties doent with us and now our father says he will transfer all his properties and mother's and mine(daughter) to his son since every thing was earned by him. But we are paying all property tax,water tax and income tax in our name. what is the legal procedure to revoke the POA and get the doents . I am educated and my mother was not educated. But we signed having faith on him.