Okla. Stat. tit. 68 § 2208
If any railroad company shall fail or refuse to make any report required by this act, or shall fail or refuse to withhold and pay the tax due from any such company within the time hereinbefore provided, it shall be liable for the full amount of such tax, penalty and costs of collection.
If any freight line company, equipment company or mercantile company as hereinbefore defined, shall refuse or neglect to make any reports required by this act, or shall refuse or neglect to permit an examination of its books, records, accounts and papers upon demand of the Tax Commission, or shall refuse or neglect to appear before the said Commission in obedience to its citation or summons; it shall be estopped to question or impeach the action or determination of the said Commission or the validity of the tax imposed hereunder.
Okla. Stat. tit. 68, § 2208