(a) Any complaint, order, notice, or other instrument issued by the Department under this subtitle may be served on the person to whom it is directed:(1) In accordance with § 1-204 of this article; or(b) If service is made by certified mail, return receipt requested, bearing a postmark from the United States Postal Service, the person who mails the document shall file with the Department verified proof of mailing.(c) Any notice that requires filing of a report, attendance at a hearing, or both shall be served at least 10 days before the earlier of:(1) The time set for the hearing, if any; or(2) The time set for the filing of the report, if any.