They lost my parcel!

How can a supposedly professional courier company lose a parcel? The couriered parcel is signed in and signed out at every stage of its journey. The parcel was signed out at Cape Town and signed in at Pretoria and then it mysteriously became "unable to locate". What is most frustrating (for me) is that the parcel contained original documents - being an application for an Irish passport. I suspect there is a ******** element involved that selectively removes parcels based on the perceived value and/or use of the contents. I would strongly suggest not making use of the Aramex courier company.