Builder failed to construct building land owner wanted to take over

Situation Builder (Sunil Mantri) has messed up the Mantri Premero project and unable / not willing to complete the project. Landowner want to take over and is putting up a condition to all buyers that we need to unconditionally withdraw the consumer cases filed against Sunil Mantri in order to proceed further. Question Can landowner not proceed with builder without all buyers withdrawing consumer cases, If Mantri handover project to landowner, then will Sunil Mantri still be bound by the agreements he made with us and What are our option after things do not move after with-drawl of cases?