I can not speak in reference to Customs and any carrier other than FedEx (who act as their own Customs Broker.) In my case I had shipments on two different occasions supposedly held up by customs, and in both cases, the problem was FedEx. In one case, the FedEx tracking site, and FedEx's customer service people, were both reporting the hold up as being with Customs, when in fact, the package never left Scotland! If you want answers, you need to call the courier. Push the issue, and have them physically look for your package to know where it is. If they tell you it is with Customs, then call Customs.