If an applicant or petitioner believes that he or she is entitled to a refund of fee, the applicant or petitioner should call the customer service line or submit a written request for a refund to the office having jurisdiction over their application or petition. USCIS will review the request for a refund and either approve or deny the request based on the information at hand. If the adjudicator finds USCIS made an error, then the officer will complete Form G-266, Request for Refund of Fee.