The Commissioner of Motor Vehicles may allow the payment of any fee specified in this chapter or chapter 247 by means of a credit card and may charge each payor a service fee for any payment made by credit card. The fee shall not exceed any charge by the credit card issuer or by its authorized agent, including any discount rate. Payments by credit card shall be made under such conditions as the commissioner may prescribe. If any charge with respect to payment of a fee by credit card is not authorized by such issuer or its authorized agent, the commissioner shall assess the payor the fee specified in subsection (f) of section 14-50.