In this scenario, you can file an FIR in the nearest police station and approach the deputy registrar with the notice stating the facts that your property has been illegally transferred, and their NOC is not secured from you to sell or transfer the property. Misrepresentation of facts and cheating is punishable under Sec. 420 of IPC.

Kindly initiate notices as early as possible to all the authorities as mentioned by you.

Please let me know should be any further clarifications required, and I would be willing to guide further.

Thanks.

You have not mentioned whether the will is forged or not ? You can go as suggested by Ld. Adv Feroz Shaikh. You can also file a suit for partition of property and challenge the will during the proceedings. Since other legal heirs are also aggrieved, it will be easy to discard the will in the suit proceedings.