Newly ordered Apple Watch not received

I ordered an Apple Watch series 3 from target.com. Email says package delivered by USPS but I never received the package. Spoke to customer service who advised me to wait a few days as sometimes USPS marks delivered when package arrives at post office and not delivered to home. Target has offered to refund me the money or send me another one. My question is if the missing Apple Watch is delivered to me or someone else could it be activated or would the IMEI code be marked as lost or stolen? Just not sure what to do as it has been 2 days since it says delivered and I still haven’t received any package from the post office.