What are the laws for leasing to buy property?

what are the laws for leasing to buy property? I made a handshake deal to buy property aggreed on paying 7% intrest and the taxes been paying for 7 years now the guy now whats the property back because he sighned a gas lease for a new green act with the state and recieved a big lump some of money i have no legal contract but i have every recipt from every payment with his signature and paid on them do i have a case in court to get my property back