So an update to this: http://bad-service.livejournal.com/2892533.html#comments
This morning we got a call from the postmaster at our post office. He went over the complaint with me on the phone, he said he had talked to our delivery women - she was saying it was because the door on our mailbox was broken. I told him that yes the mailbox door was broken because she had stuffed a package too big into it last week but that doesn't explain why she bent my stuff in half to shove it into the mailbox. He agreed, then wanted to know if we would be able to come down to the post office today and if we could bring the package if we still had it.So, my mother and I went down to the post office this afternoon. The postmaster took us in the back - to his office and he had another manager there, different than the one who took the complaint. We went over what had been happening, I showed him the packaging that says ''please do not bend'' and the comics; I explained how creases hurt the value of the comics and that the older ones had been NM before she had bent them. My mom offered to come up once a week to pick up stuff that was too big for the mailbox if our delivery person didn't want to bring it to the door and the manager there told us "its part of her job to bring that stuff to our front porch, its what she gets paid to do".
The postmaster said he would sit down and talk with our delivery women when she got back in tomorrow morning - he kept the packaging the comics came in (which was fine with me, we took pictures of it all). I also told him about the attitude of the guy who had taken our complaint; how terrible it made me feel to be brushed off and told "its just comics. He agreed that unprofessional and that it didn't matter what was being ruined, that it shouldn't be happening regardless of the item and it was behavior that was not accepted there.
The other manager gave us her name and said she would call us back to check in with us next week to see if things had changed. She also told us if it happened again to call our post office and ask for her. I'm feeling better about it all for right now - hopefully stuff will stop being ruined and the service will get better.