Packages are sometimes scanned as "delivered" before they're actually delivered. This isn't uncommon, as you can read from this Reddit post and all the google results on this topic. Even the USPS website itself says: " package may show as 'delivered' but could take additional 24 hours."
First, make sure the shipping address on your order was correct.
If it is, you can call your local post office to request the true tracking status. If the package was sent by priority mail, they can check the GPS coordinates of the delivery to verify it was delivered to the correct address. Don't call the USPS hotline as they won't be able to help without a formal trace, which could take weeks. It needs to be your local post office.
You can also place a service request by email to your local Post Office™ facility for follow-up. You will receive a confirmation number and a contact within 2-3 business days.
Please note that we don't have any further information beyond the tracking status. What you know is what we know. If it's too much trouble for you to try to reach your local post office or mail carrier, please let us know and we can file a missing mail search request through the USPS website. But it generally takes a few weeks to receive a response from them. It's usually much faster just to contact the local delivering post office.