Lost luggage on SITA bus

Hello! We just landed in Mairoi by way of Salerno. We took the SITA bus and got off at our stop, only to realize that we left a bag on the bus just after it left. Has anyone had any luck recovering lost items on a SITA bus, and if so, how did you contact them? I'm not having much luck finding a number to call for lost items. Thanks in advance :)