The Washington State Department of Transportation is cautioning customers about using Seattle-based bill payment company Doxo to pay Good to Go! toll bills. In an orange flyer being inserted in Good to Go! bills mailed to Washington drivers, WSDOT warns that “Doxo is not affiliated with Good to Go!” and that the state agency has no control over fees Doxo may charge or the timing of its payments, which can incur additional late fees.