Does the questioner want to ask "If the letter issued by the National Trademark Intellectual Property Rights and Trademarks is gone, do I need a certificate from the post office?" don't want. If a letter issued by the State Intellectual Property and Trademark Office is lost, you do not need to go to the post office to issue a certificate. You can request the State Intellectual Property Office to re-seal it; provide proof of mailing, such as envelopes, courier codes and trademark numbers, etc.