A federal judge in Washington, D.C., Wednesday angrily spoke out against the U.S. Postal Service’s failure to comply with an order he issued Election Day meant to make sure mail-in ballots were delivered on time, saying he would eventually call on Postmaster General Louis DeJoy to appear in his court.

“I’m not pleased about this eleventh hour development,” U.S. District Judge Emmet Sullivan told a Justice Department lawyer at the start of Wednesday’s hearing. “You can tell your clients that, and someone may have a price to pay for that.”