Is Unregistered Development cum Sale Agreement enforceable under law after 2 years?

Hi Team, I am land owner for 400 S yards open land situated in Hyderabad, Telangana. I had entered into development cum sale agreement with builder to construct Non commercial apartments in the open plot with 50% share ratio on a 100 Rs Non judicial stamp paper, in September 2017 and received 4, 00, 000 as advance from developer with following terms and conditions. as a land owner I have to fulfill and complete all ULC clearance certificate from (Urban land ceiling Office) and LRS from (Municipality Office), builder has to get appropriate construction permissions and complete construction but not mentioned any specific time to complete. As this property is under ULC Zone and property was not cleared by ULC office even after so many years, now I am not able to fulfill my responsibility to get clearance certificate, Now I am ready to pay back developer advance amount with interest, so I requested developer to terminate agreement, now developer demanding me 20 lakhs as compensation to cancel agreement saying he waited for 2 years and he incurred some expenses for this project. But except agreement between Developer and me nothing progress. please help me, how can I overcome this issue. Unregistered Development Agreement is not enforceable under law? and is there any bar in the Indian law for validity of Development agreement