Several years ago, I received a package and the mail carrier (don't have the same one now) shoved the package into my mailbox (how he did that is unknown to us til now). We could not get it out. I called the Postmaster at our local post office and he came out and it took him forever to figure out how to get the package out. (We has left a note with the postmaster to hold the package at th PO and put a card in our box and we would pick it up the next day, but didn't do any good).
We have a really good mail carrier now. She is so good to watch how she puts it in the box. She will even bring it to the door if it's too large to put in the mailbox or if it is raining. She is the sweetest person we have ever had as a carrier.
We always take our packages to the PO and have them hand cancel the package to avoid some damage. I guess they have so much and those machines are hard on things.