Del. Code tit. 30 § 5129
If a check received in payment of moneys due the Department under this chapter shall be returned to the Department by the maker's bank because of insufficient funds, closed account, stopped payment or any other reason, there shall be imposed upon the maker a service charge of $10 and interest at the rate of 1% per month, or fraction thereof, shall accrue on the tax, if any, from the date such tax was due to be paid. A statement shall be sent to the maker demanding payment within 15 days of the original amount of the check plus the added service charge, interest, if any, and the cost of the postage incurred in mailing the statement. Failure of the maker to respond to the demand within 15 days shall constitute cause for the Department to suspend the maker's motor fuel license and 30 days thereafter, to revoke the maker's motor fuel license.
30 Del. C. § 5129