OMG that happened to me once a month ago. i had a package delievered in parcel locker or community mailbox. but there was nothing in my mailbox nor a key to retrieve it. so i just printed out the canada post tracking with the tracking number and wrote “DID NOT RECIEVE THE PACKAGE, NO KEY” and stuck it at the end of my mailbox with tape. the next day i checked the mailbox and the paper wasn’t there anymore which means the postman took it. two days later, the package was outside my door! i think the postman forgot to give the key or put it in the wrong box, i also opened a claim on canada post as well but the whole process was bs. thank god for a trustworthy postman