DHL Express fails to deliver

An offer to purchase to purchase a house was sent down to South Africa with a delivery on a Friday. The tracking system states the consignee, a school, was locked at 14:43 while the gate is manned and the staff in admin until17:00! Offer to purchase has now lapsed as an International Courier Service, DHL, DOES NOT DELIVER ON A SATURDAY!! How is that possible for a company such as DHL which is networked internationally plus a delivery which was clearly not made as described on the tracking system!