Value of stamp paper for land partition

Sir i have purchased 8 decimile of land with my uncle at jehanabd , bihar. Due to lacs of knowledge and high additional charge of partition on sale deed the land was equally parted on sale deed. although the actual distribution was 5.67 decimile to me and 2.33 decimile to my uncle. Which is written on 1000 rs stamp paper with three witness. Now my uncle denys the share and asked half of the land. What should i do. Is 1000 rs stamp paper is a legal documents for partition.