No act or proceeding of the Tribunal or the Appellate Tribunal shall be questioned or shall be invalid merely on the ground of the existence of any vacancy or defect in the constitution of the Tribunal or the Appellate Tribunal, as the case may be.
A party to any proceeding or appeal before the Tribunal or the Appellate Tribunal, as the case may be, may either appear in person or authorise one or more chartered accountants or company secretaries or cost accountants or legal practitioners or any other person to present his case before the Tribunal or the Appellate Tribunal, as the case may be.