Responds to proposal to cut its tech off from USF funding
FCC chair attempts to close hidden back doors that threaten national security
Almost $1 billion in funds would also go to expand broadband buildouts
Auction begins July 24
Would make up to $76.9 million available for assistance
Say FCC chairman has taken steps threatening subsidy
Commissioners team up on informal request, propose means-testing USF
Call Shift in Policy 'Arbitrary and Capricious'