UPSC released a list of 734 candidates those are not eligible to write CDSE (II) 2012 this year. Reason for application rejection is non- payment of fee. UPSC did not find any confirmation of the fee from bank authorities on behalf of these candidates.
You can check your name in the list by matching registration id (10 digits) and transaction id, there might be many similar name so just search it by matching your registration or transaction id. If you have find you name and registration id in the list then you can appeal again rejection, read below for more details.
By UPSC:
Appeal against rejection, if any, may be made along with the documentary evidence by speed post OR by hand only to Shri S.R. Meena, Under Secretary (CDS), Union Public Service Commission, Room No.321,Ayog Sachivalaya Building. Dholpur House, Shahjahan Road, New Delhi‐110069. Appeal against such rejection should be received in the Commission’s Office latest by 22.07.2012.