(a) Complaint. A copy of the complaint may be served upon the respondent by certified mail or by first-class mail. The copy of the complaint may be delivered to the respondent or the respondent's attorney or agent of record either in person or by leaving it at the office or place of business of the respondent, attorney or agent, or the complaint may be delivered in any manner which has been agreed to by the respondent. If the service is by certified mail, the post office receipt signed by or on behalf of the respondent will be proof of service. If the certified matter is not claimed or accepted by the respondent and is returned undelivered, complete service may be made upon the respondent by mailing the complaint to him or her by first-class mail, addressed to the respondent at the address under which he or she is enrolled or at the last address known to the Director of Practice. If service is made upon the respondent or the respondent's attorney or agent in person, or by leaving the complaint at the office or place of business of the respondent, attorney or agent, the verified return by the person making service, setting forth the manner of service, will be proof of service.

(b) Service of other papers. Any paper other than the complaint may be served upon an attorney, certified public accountant, or enrolled practitioner as provided in paragraph (a) of this section, or by mailing the paper by first-class mail to the respondent at the last address known to the Director of Practice, or by mailing the paper by first-class mail to the respondent's attorney or agent of record. This mailing will constitute complete service. Notices may be served upon the respondent or his attorney or agent by telegram.

(c) Filing of papers. When the filing of a paper is required or permitted in connection with a disbarment or suspension proceeding, and the place of filing is not specified by this subpart or by rule or order of the Administrative Law Judge, the papers will be filed with the Director of Practice, Treasury Department, Washington, DC 20220. All papers will be filed in duplicate.