Britney Spears fails to respond to calls for court-ordered drug tests.
Federline attorney Mark Vincent Kaplan told Superior Court Commissioner Scott Gordon that there have been 14 laboratory requests for drug testing and Spears failed to respond to eight of them.
Federline has temporary custody of the couple's two children, 2-year-old Sean Preston and 1-year-old Jayden James.
Spears, a tabloid fixture thanks to her public blunders and turbulent personal life, was ordered last month to temporarily surrender custody of the two boys.
Anne Kiley, Spears' lawyer, argued the previous court order was unconstitutional and Spears did not respond to the lab phone calls within an hour, as ordered by the court, because she was sleeping.
Kiley asked that Spears be given six hours to respond to the laboratory phone requests.
But the judge said time was not the problem and noted that Spears has lost telephone numbers and changed her telephone numbers.
He suggested Spears get a separate cell phone for lab-only use.