Pawar housing agency - Plot recovery

My father naval kumar inkaji patle purchase a plot in **** from powar housing agency address.punapur chouk, Bhawani nagar, Nagpur Rajabhoj Nagar.total plot area is ****sq ft .at that time total plot is purchased by value to ****** .my father had paid ******rs by **/**/****
Remaining *****rs to be paid at the time off registry. today me saw that that plot was sold to some one else.the agency has not given any instructions about this..so i kindly request u to please help me to recover my plot.as soon as possible.