Del. Code tit. 30 § 5228
In the event that any fees, taxes, penalties or interest imposed by this chapter shall have been erroneously collected from the motor carrier, the Department of Transportation may, upon request of the motor carrier, permit such motor carrier to take credit against a subsequent tax report in the amount of the erroneous overpayment, or, the Department may certify to the State Treasurer the amount of fees, taxes, penalties and/or interest erroneously collected by the Department. The State Treasurer shall thereupon draw a warrant for such certified amount made payable to the motor carrier.
No refund of any taxes, fees, penalties or interest imposed under this chapter may be obtained except by filing a written claim with the Department before the expiration of 1 year from the earlier of:
The claim must be in such form as may be prescribed by the Department, and shall specifically set forth the circumstances entitling the claimant to the refund.
30 Del. C. § 5228