If any transportation agency referred to in this chapter is in default in the payment of the fees prescribed, other than filing fees, for a period of 30 days or more, the commission may suspend or revoke any certificate of public convenience and necessity, permit, or license of such agency, and shall estimate from all available information the gross operating revenue of such agency, and shall add to such estimate a penalty of 25 percent for failure, neglect, or refusal to report. The transportation agency shall be estopped from complaining of the amount of such estimate. In no event shall such penalty be less than one dollar ($1). Upon payment of the amount estimated and the penalty thereon, the certificate, permit, or license of such agency theretofore suspended in accordance with the provisions of this section shall be reinstated.
The commission may grant a reasonable extension of such 30-day period to any transportation agency, upon written application of the transportation agency and proper showing thereunder of the necessity for such extension.
Upon revocation of any operating authority issued to any transportation agency subject to this chapter, all fees provided for herein shall become due and payable immediately.