Ancestral property issue

Dear Sir, My my father (Bapu) and my Uncle (Vijay) distributed (before 19 years) their ancestors (their father and their one brother Raj, who died at young age without heir) property within them, with mutual understanding (only orally and in presence of some village witnesses) as follow: (1) Bapu took 23 acre and vijay took 16 acre land (Here Bapu got 6 acre extra land because out of 23 acre, 17 acre was low fertile/ unirrigated land). However Vijay got all the 16 acre land of god quality, well developed and well irrigated (this unequal distribution they made according to quality and quantity of land ). now the 17 acre barren land which Bapu had got was on Vijay's name on document. Now this year when I asked to (Vijay) to make documentation of the 17 acre land (which he had gave to my father, Bapu) on either my or my-father's name. He is denying and is asking to give back 6 acre more land which he had gave extra as compensation to Bapu when divided 19 yrs back. because now the land valuation has increased. I will be very grateful to you for your kind advice on this critical matter. Sir, Kindly do not hesitate to ask any query