“ The Renegotiation Act authorizes the Chairman of the Maritime Commission to conduct investigations in the first instance to determine whether excessive profits had been made on contracts with the Commission. A contractor aggrieved by the Chairman's determination of excessive profits may have them redetermined in a 'de novo' proceeding before the Tax Court. ”

“ It pointed out that the exclusive 'power 'to prevent any person from engaging in any unfair practice affecting commerce' (had) been vested by Congress in the Board,' 303 U.S. at page 48, 58 S.Ct. at page 462, and concluded that to grant the injunction would violate the 'long-settled rule of judicial administration that no one is entitled to judicial relief for a supposed or threatened injury until the prescribed administrative remedy has been exhausted.' Under this rule the District Court here too lacked power to grant an injunction. ”