Upon filing of a zoning appeal, the Prothonotary or Clerk shall forthwith as of course send to the governing body, board or agency whose decision or action has been appealed, by registered or certified mail, the copy of the zoning appeal notice together with a writ of certiorari commanding said governing body, board or agency, within 20 days after receipt thereof, to certify to the Court its entire record in the matter in which the zoning appeal has been taken, or a true and complete copy thereof, including any transcript of testimony in existence and available to the governing body, board or agency at the time it received the writ of certiorari.