Civil case

Dear friends Please give me proper advise about my civil case I paid advance in cash of two lakhs in 2018 January and made sale agreement for the purchase of 1 acre agricultural land . Later I learnt that there's dispute of boundaries and dispute with the owners brothers. The owner kept on seeking amount from me and I paid 6 lakhs till 2020 august among this I paid 2.5 laks via online transfer to his account and mentioned it in the 100 rs bond paper . There are 2 witnesses' signatures also in the sale agreement. Now this fellow is denying to have made any sale agreement of land with me and saying that the agreement is fabricated and fake . About the online transfer of 2.5 lakhs he is saying that he has taken handloan and returned it to me in cash. The two witnesses who put initials in the sale agreement are honest and are willing to give witness fairly . I have sent a lawyer notice demanding him to register the property in my name as per the agreement . But in response this fellow has denied to have made any agreement and says he has taken handloan and returned it to me in cash . Now what shall be my approach and how strong is the case in my favor