Are you the buyer or the seller?
If you are the seller, the buyer will let you know if it has not been delivered. Perhaps with a polite concerned note or perhaps with a Item Not Received Dispute.
If you are the buyer, you could send the seller a polite concerned note, although there is not much she can do about it, other than offer a prompt refund. Do NOT accept an offer of a replacement.
Or you can open an Item Not Received Dispute in the Resolution Centre at the bottom of this page.
The first suggestion there will be sending the seller a polite concerned note, but unless you get a prompt refund, you then escalate to a Claim.
You have 30 days from the last estimated date for delivery that eBay gave you for this.
That date is not the same as the "out for delivery" date of July 4.
Keep in mind that tracking is a Seller Protection against unwarranted claims of non-delivery. It has no benefits for a buyer except to make her worry when the tracking seems wonky.
Hmm-- before you follow either of those solutions, go in person to your local PO with your tracking number in hand, and ask if they have it. It may have been taken to the PO because of some minor problem with delivery.
