Britney Spears has angered bosses at her record label after failing in her duties to promote new album BLACKOUT. The latest release is scoring impressive reviews from music critics in both the U.S and the U.K., but the star is reluctant to attend interviews in a bid to promote it, reports TMZ.com. A source tells the website, "This album could've been so much bigger with Britney involved." However a spokeswoman for Spears' record label Jive Records says, "We absolutely stand behind Britney."