You must contact your local post office and follow their instructions. They will most likely have you file a claim. There is unfortunately nothing I can do to help you in these situations, as I have no ability to verify the package's location/whether or not it was stolen. Once something is marked as 'Delivered', any complications are USPS's job to solve. Repeated theft incidents from the same location may result in a 'soft' shop ban, meaning that I will refuse all orders sent to a problematic address and will only ship if the customer uses a new, hopefully more secure address.