Joint venture unregistered

I have entered into an unregistered agreement for joint venture for a land on August 2015 on 60:40 ratio for 1.5 acres. But the land had some legal issues like it was lying in one single RTC of 10 acres along with other 5 owners for rest 8.5 acres of land, so we were unable to go for registering the joint venture agreement as there was no proper sketch of the land. Even the owners were in good terms with me initially. The agreement was made in such a way that the owners themselves have to rectify the lands & obtain documents, they have to alienate the property & get a plan approval for the land from competent authorities by their own funds and they agreed for all the above. Later on they failed in doing all the above & requested me to complete everything from my own funds and finally they will pay back. I agreed & completed alienation in the year 2021 and requested them to complete plan approvals & come for registration for my share if 60%. They kept on postponing for 2 years & finally when i sent a notice to them, they are challenging me in court that the 1)agreement is not registered, 2)no stamp fees has been paid 3) it has crossed its limit of 3 years. 4) they are innocent & have been cheated dubiously by myself. But we have clearly mentioned in the agreement that only after they handover the approved plan we need to complete the work within 24 months & also can be extended by mutual discussion. So i am eager to know about the legality in the above issue.