Orders shipped USPS First-Class do not have guaranteed tracking updates once the item has left the United States. In a majority of instances, the package is still on its way to you. However, the tracking is simply not being updated by the carrier. In these cases, the last tracking update for the order will show that it has been received by a facility in a US city.
Customers in other countries may be able to receive tracking updates once the package reaches their country from their local postal service by referencing the USPS tracking number they were provided. For example, customers in Canada can reference their tracking numbers at www.canadapost.ca