It is believed that none of other family members, legal heir has staked a claim on the deposit with the bank/BM. Kindly check, if the nomination is registered on the FD/deposit receipt.
You can submit a written letter, enclosing self attested copies of your ID, address proof, pan card,addressed to BM of the bank, mentioning date of your previous representations in person, and demanding disbursement of paymnent at once. Obtain the acknowledgment of your letter under seal and full original signature by hand and ask the BM to put his name and employee number. YOu may mention that you are the registered nomineee, and you are showing the original proofs as per KYC rules to BM, copies of which are enclosed with your letter.
If the BM delays, you may lodge a complaint with nodal officer and chairman of the bank stating that the BM is exceeding the rules and causing harassment, and seek relief.