The board shall have power, on its own motion, or on appeal, to remove, transfer, or review any claim pending before, or decided by, a referee, and in any such case and in cases where a further appeal is allowed by the board from the decision of a referee, may affirm, modify, or reverse the determination or revised determination, as the case may be, of the department or referee on the basis of the evidence previously submitted in the case, or direct the taking of additional evidence. When any claim pending before a referee is removed or transferred to the board, the board shall afford the parties and the department reasonable opportunity for a fair hearing. The parties and the department shall be duly notified of the board's final decision and the reasons therefor. A complete record shall be kept of each case heard before the board. All testimony at any hearing before the board, whether on appeal or otherwise, shall be taken by a reporter and recording device. An unabridged transcript and audio recording of the testimony shall be made available, at cost if not used for unemployment compensation purposes or a subsequent appeal, to the parties and their attorneys or other representatives upon written request to the board.