The only true "tracking number" available is with UPS shipping.
Our US Postal Service shipments are all sent with a "delivery confirmation" number, which only tells us if you received the package after the fact. International shipments via the USPO can not be tracked or confirmed. UPS shipments can.
If you have selected USPO shipping in checkout, you have exchanged your right to know if or when a package will be delivered, for the reduced price offered.