How did i get a card from someone yesterday without it going to my mailbox?

       I didnt get to see the person that delivered it cause my apt manager gave it to me, sometimes newsletters will post my birthday and this one this and the card was from massachusetts, so how did the card manage to be stamped like the post office stamped it but it didnt go to my mailbox and how did they mail a small cake from safeway? i wouldve thought the card at least wouldve gone to my mailbox, so how did the person get my mail and i dont think a maillady would have time to go to safeway, so how did they do it? i did write her back but its just weird that i didnt get it in the mail like i was supposed to.