When any motor carrier shall be delinquent in paying the mileage tax as provided in this chapter for a period of 60 days, the Department of Revenue shall notify the Alabama Public Service Commission of such default in writing, and the Alabama Public Service Commission may suspend or may revoke, after public hearing, any and all certificates of public convenience and necessity or permits that are in force and effect of said motor carrier which is in default of the payment of said mileage tax.