I don't know where you got that from, StratComm. Must have been fan fiction, I think.
Radio communication should still have been possible, it is true, but even still, it wouldn't be much of a conversation. Assuming anyone had answered a signal from the GTVA, which they obviously didn't according to the tech room, it would have gone something like this.
GTA: "Are you all dead?"
*eight years later*
Earth: "Not yet. There's civil war between the inner and outer planets, though."
Terran radio guys from the Antares Federation operating in Vasudan-controlled Alpha Centauri: "Well, let us know how it goes, eh?"
*eight years later*
Earth: "All things are under control, now that the Glorious General Rashtalin is in command. All will surrender to his Gloriousness's command!"
GTVA: "Right... Okay then, umm... yeah."
*eight years later*
Earth: "What? What was that all about? 'Umm... yeah' what?"
GTVA: "General Rashtalin. Wasn't he in control of things? What the hell is going on there?"
*eight years later*
Earth: "Hey, this is, like, totally cool! My dad bought this old government space transceiver thingy a couple of years ago, after he took control of the energy sector or somethin'. Are you guys, like, in Cappella or somethin'? That'd be totally far out, man."
GTVA: "This is the Galactic Terran-Vasudan Alliance. Is there anyone there besides beach-bum kids playing with former government property? We've just had another encounter with the Shivans, and we've also got some technology that might be able to reopen the link between Sol and Delta Serpentis. We wish to speak with the heads of government in the the Sol system, if there are any. HelloooOOOOoooo
oooo?"