Ezenkosi, who were promoted last term, will face another spell in the National First Division, with a 2-2 draw against Black Leopards sealing their fate in midweek.
Sono, who doubles as Cosmos manager, believes he alone can ensure a swift return to the top flight.
"Why do we have to fire the coach? He has done nothing wrong. It's just that we were unfortunate this season," said Sono in the Sowetan.
"Cosmos have been relegated to the First Division because we did not have an experienced striker, or strikers, to score more goals.
"I'm still proud of these boys. Despite the fact that we have been relegated, we played very well during the season, but the problem of not scoring goals has resulted in us getting too many draws (13).
"We are keeping the coach (because) I'm the only person who can get Cosmos back into the Premiership," he said. "Even Jose Mourinho would not survive. Cosmos will be back in the Premiership shortly," concluded the Black Prince.