From my Notebook >
Problem: You know your package was delivered to an Amazon Locker. But you haven’t received an email or a text message telling you the retrieval code! You check your order information, and still can’t find the code.
Solution: You have to go to the Amazon Message Center in your Amazon account. Once you’re in the Message Center, scroll down until you find a message that says “Your package is ready for pickup…” click or tap on this message to get the code.
I hope it was helpful! This was super annoying to have to figure out, because Amazon doesn’t mention it in the shipping information, and you only have 3 days to retrieve your package, and sometimes the notification never arrives!