We have seen plenty of cases where this happens. Most of the time it's just an error with the carrier and the item shows up within the next few days, but there are exceptions.
If your tracking information says that your package was delivered but you haven't received it yet the first step is to contact the carrier.
Unfortunately, we are not liable for these kinds of situations, once the package leaves our facility we have very limited access to specific shipment details. For this reason, we recommend that you reach out to the carrier for detailed information for your delivery.
If you still need help please send us a support request, we are always more than happy to assist!