Erlanger is where the GSP plant is.
Which four days?
The plant appears to be closed on Sundays. And like many businesses works with a smaller staff on Saturdays.
The plant not only redirects your shipment (and many thousands of others going to nearly 200 countries around the world) but also pre-clears it for Canadian customs and sales taxes.
More important.
Wrong question.
The right question is : What date did eBay give you for delivery?
Has that date passed?
If it hasn't, relax. It is on its way albeit during a period when political interference is such that post office clerks are advising shippers to use the more expensive FedEx services rather than USPS which has been overwhelmed by a pandemic surge in online buying and shipping along with sick workers, workers using leave to care for dependents and political interference with the normal flow of mail including refusing to allow overtime even for carriers who still have packages in their trucks.
If your parcel does not arrive by the date eBay gave you, you can open a Not Received dispute in the Resolution Centre at the bottom of this page. If the GSP cannot prove delivery (not shipping, delivery) you will be refunded.
Bonus, if you are refunded and the item turns up late, the GSP doesn't want it back.
If you are not home when the package is delivered, the carrier will leave a Notice telling you where and when you can pick it up.
TL/DR -- it's on it's way. Stop obsessing.
