If any auctioneer, broker, agent, or factor, shall fail or refuse to make a return, as required by section 729 of this act, to the mercantile appraiser of his county, when requested so to do, it shall be the duty of the mercantile appraiser to assess him or it with the maximum license tax provided for by the act or acts of Assembly imposing an annual license tax upon such auctioneer, broker, agent or factor. A certified copy of such assessment shall be forwarded to the auctioneer, broker, agent, or factor, which assessment shall be final and conclusive and without appeal, and such auctioneer, broker, agent, or factor, shall not be permitted, in any action brought to recover such assessment, to deny the correctness thereof.
72 P.S. § 1718