>- Customs should notify you if they hold your package but there are times when an item just disappears

You are right about the problem with customs. It is often not known when an item goes in, where it goes internally, or when it comes out. While in most countries, the customs process is reasonable, I have seen things take over a month and customs is the one place where an item is most likely to disappear in my experience.

If the product is valuable, it is best to use a courier such as UPS / FedEx, that will hand carry the item through customs. But, it is often too expensive.

Also, another difficulty is that the post customs couriers are often not very diligent in contacting the recipient and providing notification that the item is ready for delivery. I have seen items returned where the recipient had never been notified that it had cleared customs.

Yes, they are a good company but single frequency zappers have been long obsolete.