When a taxpayer succeeds on a refund claim they are often entitled to interest on such refund. Unfortunately, departments of revenue sometimes take unlawful steps to prevent taxpayers from recouping such amounts. A recent decision of the First District Court of Appeal of the State of Florida (the “Court”) scolded the Florida Department of Revenue (“Department”) for taking such action. SEI Fuel Services, Inc. v. Fl. Dep’t of Revenue, No. 1D2024-2098 (Fla. Dist. Ct. App. Oct. 22, 2025).

The Facts: SEI Fuel Services, Inc. (“SEI”) double-paid its Florida motor fuel taxes. Realizing its error, SEI sought a refund of the double payment, which the Department denied despite acknowledging that SEI had in fact paid tax twice in error. On review, the Court determined that SEI was due a refund and ordered the Department to issue such refund. The Department issued a warrant for the refund amount but included no interest. 

SEI “wasted no time” sending the Department a demand letter for the interest owed. The Department failed to respond to the letter, causing SEI to seek mandamus relief in Florida circuit court. However, the circuit court denied SEI’s request, concluding that it did not have jurisdiction to issue such an order. Undeterred, SEI appealed once again to the Court.

The Law: Florida law provides that interest “shall be paid on overpayments of taxes, payment of taxes not due, or taxes paid in error” so long as the refund application is timely and complete and contains the necessary information for the Department to pay such amounts, including “sufficient information… to permit mathematical verification of the amount of the refund.” Fla. Stat. § 213.255. Interest commences 90 days after a complete refund application has been filed and is paid until a date no more than seven days prior to the date of the issuance of the refund warrant. Id. at (4), (6); Fla. Admin. Code Rule 12.26.004(2)(b).

The Decision: Finding SEI’s “separate action for interest… ripe, due, and owing” the Court rejected the circuit court’s erroneous conclusion that it did not have jurisdiction. Turning to SEI’s refund application, which the Department never argued was incomplete, the Court easily concluded that SEI was owed interest on its refund claim. Accordingly, the Court reversed and remanded SEI’s case to the circuit court with directions to grant SEI’s petition for writ of mandamus and to determine the amount of interest owed.

The Takeaway: This case serves as a good reminder to taxpayers not only to check amounts received from states to ensure that they are accurate, but also to not be deterred when a state fails to respond to a proper refund request or demand letter. Departments of revenue generally waste no time in seeking interest on back due taxes. Taking a page out of the departments’ books, taxpayers should use their available resources to make sure that they are receiving their fair share of tax and interest owed by those same departments.