India Post — Not able to encash my national saving certificate

Address: Pune, Maharashtra, 411036

I had purchased one national saving certificate on[protected] at Gurgaon Sector-14 post office. Its maturity date is over and I am living in Pune now. I am not able to encash my NSC. I have visited the Pune head post office. They informed me that they are not able to get Gurgaon sector-14 pin code in their system. I have also got negative response from Hadpsar and Mundhwa post office.
Please provide any solution for this issue.

Email id : shailendra.[protected]@gmail.com