Is this a GSP order?
You can't-- or it really isn't easy.
Contact your seller. Ask for the date of shipping, service used and tracking number.
Enter the tracking number into USPS website. (If your seller is in the USA).
If the item was sent to Kentucky, don't panic.
That means it is somewhere between Kentucky and you. But the information is hard to find and may not yet be public.
Now.
If the item gets to your house and you are not home, the postie (or courier) will leave you a notice about where and when you can pick up your parcel.
But.
If the item was low cost or from China, there is a good chance that it was not tracked.
This is not a problem.
Allow 20 days for delivery from North America and 30 days from Asia.
If those dates have passed, go to the Resolution Centre at the bottom of this page and open an Item Not Received Dispute.
The first step is to contact the seller, but you already did that (above).
If the seller cannot prove the delivery of the item, you will be refunded in full.