India Post — Bribe taken by postman to hand over the passport

My brother Vivek Jaiswal applied for passport for which all the procedures was done and Police verification was also cleared and thereafter the passport was couriered through speed post PP[protected]IN which was out for delivery on 16/03/2023. But as my brother had to join his new job on 13/03/2023 at Lucknow, he shifted there. So in order to receive the passport, he wrote and signed an authorization letter in the name of Lakhi Shankar Jaiswal (father) to receive the same on his behalf.
But the Postman was reluctant to provide the same and called my father to the Post-office on 17/03/2023 and has forcefully taken bribe of Rs 1200 to handover the passport, threatening to return the passport back to the passport office mentioning that the Holder was not available, due to which the father has provided the same as it was urgently needed for joining formalities.
Requesting you take some strict action and refund the money. Postman Mobile No. [protected].