Ownership of Joint Water Boring between 2 Independent Houses

In Feb-2019, I and one of my relative purchased a plot of 200Sq.Yard in 2 pieces (15*60 each piece). In June-2019 after registry and sub-division of Patta, we started construction in joint, same in every aspect with 1 contractor. My relative proposed me to Dig a water borewell for water supply in construction and future use under joint ownership. In the day of boring, my relative called me in my office and said there is technical issue to align boring truck as we already dig the plinth level of surface and boring is possible in his side of plot. After a long telephonic conversation, we agreed for boring in his piece of land. We shared all construction and boring expenses, majority of which is in banking mode. We have been using joint water supply through internal pipe fittings. All repair and maintenance expenses have been paid equally since then. Suddenly, it came to know in my knowledge that my relative sold his house silently and suddenly by telling lie to buyer that it's his personal Boring in his part of land, basis of which buyer agreed for purchasing. What are the legal remedy I can have provided i have all recordings of our conversation proposal, technical issue for digging bore in his piece of land. Calculation of expenses and payment proofs by bank or cash, bills for boring pipes in my name.