Flysafair I need my phone back

On Sunday the 1st of September 2024 I accidentally left my phone on FA 478 from Lanseria to King Shaka Airport. My flight was from 19h50 to 21h00. I sent the airline an email first thing in the morning on the 2nd of September. I called the airline at 07h00 in the morning to ask if they can check my phone for me. Unfortunately they could not find my phone. Can someone explain to me how airlines work. If they not check if we left our items in the flight after each trip? I need an explanation from FlySafair. I don't want to accuse anyone but either one of the crew members took my phone or the passenger to occupy sit number 23A took my phone. This was the last flight of the day and I called the airline at 07h00 in the morning. I need an explanation.