Why was there no radio of the VSC message which prompted Hamilton’s apology? | Formula 1

Lewis Hamilton apologised to his Ferrari team for his costly decision not to pit during the second Virtual Safety Car period during yesterday’s Singapore Grand Prix. According to the team, Hamilton was unwell after the race, visited the Medical Centre and was excused from speaking to the media. He therefore did not explain what went wrong. However he revealed the decision not to pit under the VSC was his in a radio message to Ferrari after the race. “I let you down today with that strategy,” he said.