Unique tds certificate number

I withdrew money from NSS-87 on 15.03.2014 from Kolkata GPO. I was issued Form No. 16A by the Post Office showing the details of payment,tax deduction etc on the same day. Now I want to file my income tax return where " Unique TDS Certificate Number " is required to be furnished. I do not find this certificate no.in the Form No. 16A issued by the Post Office. And when I check my 26AS,all other details are there except the unique tds certificate number. I approached the Post Office for this certficate no. but they don't oblige. As I have to furnish this number for online submission of IT return, please let me know your views. S K Ghosh