Builder cannot convey its interest to another builder. When the builder has sold the flats to its allottees then he cannot transfer his interest in the property to another builder. It is illegal and has no legal implication over the flat owners. After completion of the project the builder should transfer his interest in the welfare society formed by the flat owners.
This is the procedure towards the transfer of share to the flat owners. Thereafter, the society, consisting of the flat owners, shall decide how to use the property in the welfare of the members. The society shall issue share certificate to the legal flat owners. An illegal flat owner cannot claim share therein. It is against the interest of the flat owners to introduce another builder after sale.
File a complaint before the society registrar
First of all your society should file a complaint before the society registrar for stopping the interference of builder in the daily business of society. The builder has the obligation to transfer the interest to the society. Thereafter, the society shall take further action or decision regarding the use of land.
Lodge an FIRThe society should also register a FIR before the local police for the offence of criminal trespass. The person other than the inmates of society has no right to use the road without permission of the society. If they are using the road on the behest of the builder then the criminal case is made out against him also.