lost personal belongings

On the 19 February 2016 I traveled from Pietermaritzburg Airport to O.R. Tambo international Airport at 18:25. when I arrive at O.R. Tambo I forget my personal belongings on the seat 11A. I was the last person to come out on board and the bus was already leaving, so I could not go back to take them. I called the Airlink lost and found department three times in one week but never got a positive respond.<br> .How possible is it, that my personal belongings disappear inside the flight not even the cabin crews or cleaners never saw it?