Regarding Power of Atorny to builder

Sir, We have a plot in Nashik Maharashtra which was leased by us one religious and charitable trust in 1954 around. Actually the trust sold the plot but we don't have the agreement original papers so it is on lease henceforth. We had a old house in that plot which we had given for development and reconstruction of building to a builder in 2001. My mother- in - law and MyBrother in law and my husband was the benefice-res for the development agreement. Meanwhile all the benefice res are pass away (Death) . Now Myself and my 2 sister in law are there . We have put our and kids name of property card. The builder has not completed the construction till date. It's almost 18 year completed . He also not taken some permission from charity commissioner before construction which was essential . The shop he has constructed on ground floor also sold by him. And he has given our consideration of flat and cash as per our agreement. The flat possession is with us but legally the building has not got the completion certificate. and not completed also. Now the builder is forcing us to continue Power of Attorney. We are widows and don't want to continue with him. Can we do our self the completion of building . The civil court case last 2 years is going on. Still the issues are not framed.