LOST BAG

I was on the BA 6247 flight from Johannesburg to Cape Town last night, because I had another bag with me I left my small handbag underneath my seat. It was a small black handbag, I have called the Cape Town lost luggage and Johannesburg office because I was told that the plane went back to Johannesburg. No one seems to have seen my handbag, see I don't understand how a bag can just 'disappear', I am under the impression that your planes are cleaned each time they land?? SO how did the cleaners in Cpt and Jhb not see my bag? My ID, cards and a bunch of cash were in that bag and that might be the reason that 'no one has seen my bag'. This is unacceptable!! Why cant you guys trace who cleaned the plane in Cape Town and find out what happened to my bag???