Name of uncle in property docs but not on stamp paper what to do

we have shared property on my uncle's name. at the time of property distribution the land was given to my father but the name was my uncle in property document.the distribution is written on normal paper not on stamp paper.now their children don't want to give the property to us bcoz there is no mentioned name in the document.. and in document plot size given is large but in real the plot size is small.because city survey cancle the registrationof the land