Ill. Admin. Code tit. 86, § 950.250
a) After determining that an employer is subject to penalty under the Act for a calendar year, the Department shall issue a notice of proposed assessment to the employer, stating:
b) A written protest against the proposed assessment may be filed with the Department, setting forth the grounds on which such protest is based. (Section 85(c) of the Act) A protest must be in writing and must include the following at a minimum:
e) If the protest is filed within 120 days after the date the notice of proposed assessment is issued, the Department shall reconsider the proposed assessment and shall grant the employer a hearing. As soon as practicable after the reconsideration and hearing, the Department shall issue a notice of decision to the employer, setting forth the Department's findings of fact and the basis of the decision. (Section 85(c) of the Act) The decision of the Department shall become final: