Conn. Gen. Stat. § 31-270
If an employer fails to file a report for the purpose of determining the amount of contributions due under this chapter, or if such report when filed is incorrect or insufficient and the employer fails to file a corrected or sufficient report within twenty days after the administrator has required the same by written notice, the administrator shall determine the amount of contribution due, with interest thereon pursuant to section 31-265, from such employer on the basis of such information as he may be able to obtain and he shall give written notice of such determination to the employer. Such determination shall be made not later than three years subsequent to the date such contributions became payable and shall finally fix the amount of contribution unless the employer, within thirty days after the giving of such notice, appeals to the superior court for the judicial district of Hartford or for the judicial district in which the employer's principal place of business is located. Said court shall give notice of a time and place of hearing thereon to the administrator. At such hearing the court may confirm or correct the action of the administrator. If the action of the administrator is confirmed or the amount of the contribution determined by the administrator is increased, the cost of such proceedings, as in civil actions, shall be assessed against the employer. No costs shall be assessed against the state on such appeal. The amount of any judgment rendered in such proceedings, with costs, shall be collected either on execution, as provided in civil actions, or as provided in section 31-266.
Conn. Gen. Stat. § 31-270
(1949 Rev., S. 7540; 1953, S. 3088d; 1967, P.A. 790, S. 19; 1969, P.A. 456; P.A. 78-280, S. 2, 6, 127; P.A. 88-230, S. 1, 12; P.A. 90-98, S. 1, 2; P.A. 93-142, S. 4, 7, 8; P.A. 95-220, S. 4 -6.)
Cited. 125 Conn. 302; 126 Conn. 115; 127 Conn. 176; Id., 181; 128 C. 87; 133 Conn. 117; 135 C. 103; 314 U.S. 569; 175 Conn. 269; 179 Conn. 507; 216 Conn. 237; 225 Conn. 99. In appeal from the action of administrator, the court must try the issue de novo. 8 CS 144. Cited. 9 CS 237. The employer must keep accurate records of expense accounts. Id., 244. Cited. Id., 429; 11 Conn.Supp. 340; 22 Conn.Supp. 100. On appeal, court's function is only to ascertain whether administrator's conclusion was unreasonable, arbitrary or illegal. Id., 104. Cited. 42 Conn.Supp. 376.
See Sec. 31-272(b) re limitation on fees and costs in proceedings regarding claims for benefits.