Theft from Plane

I flew from OR Tambo to Cape Town Airport on Friday 17 Nov 2017 on flight JE147. When I left the plane in Cape Town I accidentally left my tablet in the seat pocket. On Saturday I called the airline to request that they please investigate. To the credit of Mango they did actually call me back a while later to inform \me that it was not there. Now, I do realize that it is my responsibility to take my stuff with me, but, it is Mango staff who clean the plain after everyone has disembarked. It is obvious that anything which was left in the plane is there for the cleaning staff to take! They do it, because they can and nothing happens. This is such a sorry state we are in where people can just take what does not belong to them, and everyone just accept it as OK. I called the customer complaints line, and I can hear the lady chatting to someone else in the background while I am telling her my sorry story! The sad part is that all the other airlines would probably be just as bad!