The Voice coach Will.i.am has hit out at record label Universal over the failure of last year's winner to succeed in the charts.
Leanne Mitchell's debut single did not even reach the top 40, while her album recently missed out on the top 100.
The Black Eyed Peas star told the Radio Times: "The record company should be freakin' embarrassed. Somebody should be held accountable. These singers are on television every week. So you've already accomplished things that stars don't accomplish."
Will.i.am said that it was a mistake that a record was not ready for release within days of the winner - who was coached by Sir Tom Jones - of the BBC1 show being announced.
"Do you wait a year later? Somebody should get slapped because you waited too long.
"The show paid all this money for make-up, the lighting guy, wardrobe person, editor, director. Where are the b****y songwriters and producers? Boom! Somebody should be ready," he said.
"If you're having performers sing other people's songs, you should have a whole bunch of songs ready in your arsenal. It's hopeless to release a record so long after the series finished, especially in the attention deficit disorder society that we live in today."
He admitted that aspects of the show, which has returned for a second series with fellow coaches Sir Tom, Jessie J and Danny O'Donoghue, needed to change. He joked about dunking contestants in the show, which lost out to Britain's Got Talent in the ratings, in water.
"If it was always blind auditions, you'd get bored of that, too. I think something has to happen at the end that is just as unique. As the series nears its end it needs to be better than it was at the beginning," he told the magazine.
"Something like where you could actually dunk 'em: 'I don't like 'em,' and they're in the water. F***ing bubble singing. Pshhooooo.... An exit button and you just catapult them out. Pshhooooo."