India Post — harassment on getting nsc duplicate certificate

Respected sir/madam,

I am soumendra nath singha from west bengal. I had purchased 6 nsc certificates whose value 10000 each from kheput post office, west medinipur. Unfortunately i lost all these certificates. To get the duplicate certificates i have submitted all the relivent documents and kheput post office send it to their head post office "tamluk head office". After some days i received a letter from tamluk post office, they asked me to contact them as some of the claim papers are incorrect. I went there and rectify all the documents and submitted all the asking documents. Now again got a call from tamluk post office saying one document has a problem. But when ever i go there they say that concern person is not here please come again.
It's been almost a year still they are not taking any action. Case file no d6-05/n/04/17-18
Please let me know what can i do next.

Regards,
Soumendra