Extinguishment of certificates requires physical destruction in presence of a merchant banker and auditor within prescribed buyback timelines. Extinguishment of certificates follows Regulation 12 mutatis mutandis; the company must verify acceptances within fifteen days of payout and must extinguish and physically destroy bought-back certificates in the presence of a Merchant Banker and the Statutory Auditor on or before the fifteenth day of the succeeding month, ensuring all securities are extinguished within seven days of the last date of completion of the buyback.