Britney Spears fans in Vancouver are demanding a refund after the singer walked off the stage for 30 minutes in the middle of her concert. The popstarblamed her bizzare behaviour on poor ventilation. An announcement was made to the sold-out crowd of 18,000, stating “it’s become uncomfortable and unsafe for the performers, including os Spears.” When Britney did return, she proceeded with the show without offering an explanation or an apology to the crowd. Angry fans say they did not “receive due value for their investment” and want their money back. Some fans have gone so far as to set up a website demanding a refund for the concert.