For work, parts were shipped to us via DHL. About once a month the shipment would not arrive. The people I worked for had signed an agreement that the driver could sign for the delivery. When questioned if they delivered, they would bring out their book and show their signature. Next question was where did you deliver it to? Sometimes it got found at another shop and they might phone. I think some the competition kept as "free parts", all instrumentation stuff so expensive. Some of this could hold up getting a facility back online. Some suppliers would ship UPS or FedEx, but some only used DHL. Of course the oilfield rednecks blame you for not getting the parts. Drive you mad as a rabid badger!