The event was cancelled or changed
If the host cancels, paid passes that were not scanned and unplayed song requests are refunded automatically.
When a host or an admin cancels an event, you are emailed the reason. Paid passes that have not been scanned are refunded to the original payment method, and song requests that were not played are refunded too. Details are in Refunds for event passes and Refunds for song requests.
If an event was very different from how it was advertised, you may have rights under consumer law; see Your consumer rights.