An employer desiring to appeal a combined tax rate assigned to the employer shall file, within thirty days of the mailing of the notice of the combined tax rate assigned or within thirty days of the delivery of said notice in the absence of mailing, an application for review and redetermination. Said application must be received by a Department office prior to the expiration of the thirty-day limit.
220 Neb. Admin. Code, ch. 11, § 002