Laura Mvula has revealed that she learned she had been dropped by her record label via a "seven-line email".
In January, the artist's former manager met with Sony and was told face-to face that her contract was not being renewed.
Mvula revealed that her label had dropped her in a Twitter post in January 2017 but did not say how.
However the Mercury Prize-nominated singer has since told the BBC that she only learned of this in a forwarded email.
"I didn't see anyone, I didn't hear anybody's voice. I just read words," she said. "It felt so cold and cruel.
"Not even the fact that I was dropped, the way that the whole thing happened. To be treated like that doesn't feel quite just."
Sony confirmed the way Mvula was dropped to the BBC but declined to elaborate.
"I was definitely naive in the beginning," Mvula said in her recent interview. "When I was signed, I thought when someone says, we love you and we're with you until the end, that's what they mean."
Mvula was signed to Sony subsidiary RCA Victor in 2012 in a five-album deal.
Her debut record Sing to the Moon was released the following year to critical acclaim, earning her nominations for the Brit Awards, Mercury Prize and Ivor Novello awards.
A follow-up, The Dreaming Room, was less commercially successful and failed to break into the top 10 on its release in June 2016.
Mvula is currently working on the music for a production of Antony and Cleopatra which is being staged by the Royal Shakespeare Company, which she said is "a huge moment [for me] creatively", adding that audiences should expect "plenty of groove and funk".
The new production of Antony and Cleopatra opens at the Royal Shakespeare Theatre in Stratford-upon-Avon on 23 March.