The USPS has rekeyed the large box parcel lockers. If you receive a locker-style key in your mailbox, pair it up to the large box it is associated with to retrieve your packet. Once the key has been used, it will automatically lock itself into the box for the postman to reassign to another homeowner for their package. Please check your mailbox routinely to ensure your packages are retrieved in a timely manner and keep the box from being tied up for an extended time.
If your package is not retrieved in a timely manner, the postman will take your package back to the post office and leave you a slip in your box to pick up at the post office. If not picked up there quickly, USPS may return your package to the sender or dispose of it.