Placeholder Assessee code allowed where first-time payer lacks code; banks may accept countersigned challans under certification. Where an assessee lacks a 15 digit Assessee code because the payment is a first-time or one off CBEC remittance, banks may accept GAR-7 challans quoting fifteen 9s as a placeholder provided the challan is examined and countersigned by the concerned Authority of the relevant Commissionerate certifying that the assessee has not applied for the code, is a first-time payer, and is not likely to remit dues in future.