"That turned out to be an empty offer," Grassley said on Wednesday.
Grassley first wanted to question Paul de Sa, who has now left the agency. Grassley then requested a meeting with Josh Gottheimer, but the senator said the FCC never responded to his request.
"It’s unfortunate that this agency operates as a closed shop when the public’s business ought to be public. It adds insult to injury to promise openness and fail to fulfill the offer," Grassley said.
He has promised to block President Obama's two FCC nominees until the agency releases its internal records on LightSquared.
FCC officials have noted that agencies usually only respond to inquiries from lawmakers who serve on committees with jurisdiction over them.
Republicans on the House Energy and Commerce Committee, which oversees the FCC, requested infromation from the agency about LightSquared last week.
FCC officials say they plan to comply with that request.
"The good news is a key House committee is trying to shed light on the FCC’s thinking on LightSquared," Grassley said. "Some transparency might be required of the agency after all.”