(a)Service. Except as otherwise provided in these rules, each party who files papers is responsible for serving a copy thereof upon the presiding officer and upon every other party or the attorney or representative of record of that party. A copy of all papers filed by the presiding officer or the Board, except for the transcript of testimony and exhibits, shall be served upon each of the parties. Service may be by personal service, private delivery service, or by express, certified or regular first-class mail. If a party is not represented, service shall be made at the last known address of the party or an officer thereof as shown on the records of the FCA.(b)Proof of service. Proof of service of papers filed by a party shall be filed before action is to be taken thereon. The proof shall show the date and manner of service, and may be by written acknowledgment of service, by declaration of the person making service, or by certificate of an attorney or other representative of record. Failure to make proof of service shall not affect the validity of service. The presiding officer may allow the proof to be amended or supplied, unless to do so would result in material prejudice to a party.