Lauryn Hill, Grammy-Award winning artist, could face jail if she fails to pay $504,000 in taxes by May 6

(CBS/AP) NEWARK, NJ - A Newark judge postponed singer Lauryn Hill's sentencing on charges of tax evasion Monday. The former member of the Fugees has reportedly failed to pay the more than half a million dollar in income tax she owed from 2005 to 2007.

The singer is scheduled to be back in court on May 6, and her attorney said he expects her to have paid the full amount she owes by then.

Last year, Hill admitted that she failed to pay income taxes on $1.8 million in earnings between 2005 and 2007. According to CBS affiliate WCBS, Hill stated in an online post  that she withdrew from society to guarantee her family's safety and her own.

At the time she pleaded guilty, her attorney said she would pay restitution by the time of her sentencing. But it was revealed Monday in court that Hill has paid $50,000 of a total of $554,000.

The total Hill owes is in dispute. Her attorney, Nathan Hochman contends it is slightly less than $1 million, counting civil penalties and interest, while the U.S. attorney's office estimates it at a little more than $1 million. Hochman accused the government of trying to pad the amount because once it surpasses $1 million, the sentencing range for Hill under federal guidelines would increase from 24 to 30 months to 30 to 36 months.

U.S. Magistrate Judge Madeline Cox Arleo criticized her for relying on the promise of a recording contract to pay the tax bill.

"This is not someone who stands before the court penniless," Arleo said to Hill's attorney, Nathan Hochman. "This is a criminal matter. Actions speak louder than words, and there has been no effort here to pay these taxes."

Her attorney, Nathan Hochman reportedly said that Hill is planning to sign a loan against two properties which would allow her to to pay off her tax debt by the next court date. 

Hill rose to fame during her time with the group The Fugees. She later launched a successful solo career releasing her first album tittled "The Miseducation of Lauryn Hill" that sold 8 million copies, says WCBS.