Obtain certificate from the TTE /Conductor in case of PARTIALLY waitlisted e-ticket, LESS NO. OF PASSENGERS travelled, A.C.FAILURE, TRAVEL IN LOWER CLASS. This original certificate must be sent to GGM (IT), IRCTC Ltd.,
Internet Ticketing Centre, IRCA Building, State Entry Road, New Delhi-110055 after filing on-line refund request for claiming refund.
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You can see the same wordings in every E-ticket Important points.