Okla. Stat. tit. 40, § 2-616
If the Oklahoma Employment Security Commission or its representative determines that an individual has been overpaid unemployment benefits pursuant to paragraph 1 or 2 of Section 2-613 of Title 40 of the Oklahoma Statutes, the individual shall be sent a notice of overpayment determination. If the individual disagrees with this determination, the individual may file an appeal of the determination with the Appeal Tribunal within twenty (20) days after the date of the mailing of the notice to the individual’s last-known address or, if the notice is not mailed, within twenty (20) days after the date of the delivery of the notice. If the individual fails to appeal the determination within the time provided, then the determination will be deemed final and no further appeal shall be allowed.
Laws 2002, SB 1404, c. 452, § 15, eff. November 1, 2002.