The service fee is something that an organizer can choose to have on their tickets for their event.
They can choose to have a service fee per ticket, per purchase, or choose not to apply it at all.
Whether a refund is made including/excluding a service fee* is a decision made by the organizer. If you have any questions about this, you should contact the organizer directly.
*The service fee is a fee charged to allow you to book tickets and have them distributed through the available distribution channels: eTicket, Ticket Agent, or mail, and to cover the costs of the ticket and sales network.