If the concert was canceled by the organizer, you can request a refund. But if you want to cancel the ticket purchase for personal reasons or if the concert is canceled due to a natural disaster, you must follow the terms of service of the ticket purchase. Even if you are allowed to request a refund, there is a period of time in which the request must be made, so first check the terms. If you don’t clearly understand why a refund is not being given, ask the company selling the tickets for an explanation.