If the department, after a hearing upon complaint or on its own initiative, determines that a charge by any contract carrier by motor vehicle or any carrier regulation or practice affecting a charge contravenes the policy in RSA 266-A:1 or gives an unreasonable advantage to any carrier in competition with another carrier, the department may, after giving consideration to the cost of the carrier's service and the public interest, order:
(I) A new charge; or
(II) A new rule or practice.