Tcs/tds return quary. :lost token number

Dear sir, i have a small query. I filed TCS retun for 3rd Qty 2012-13 which i want to revise now. But unfortunately i lost my Acknowledgement given to me by NSDL(karvy). As we know we need to quote Token number of original return to revise it. i met the karvy NSDL center and requested them to give a duplicate copy but they told they don't have record. nw kindely advise e how to proceed. Regards, m.s.k.sai ACA,ACMA