I purchased a old tenat room in redevelopment project?

Sir I have purchased a old tenant room in mumbai which has gone in redevelopment the landlord of the building has given development rights ti builder the tenant has already done with the consent of the builder and has all the legal documents like rent receipt elextric bill and name in assesment and mhada extract list the main reason for this question is when we went to the landlord he is asking padgi money even after the consent with builder and when we ask the builder about it he is saying in the end whi is giving gou the revelop flat ? Its from me so you have to give me transfer money not the landlord its a big confusion as why these people are not giving me clear picture to what should i do , am confused here as they are asking a lot of money for it and both of them are like come to me. Please suggest me if there is some law in which i can purchase a flat from old tenant without concerned of landlord of the building or the developer Which document should i make from the tenant so i cannot have problem of my title in future Please help me over this.