Same thing happens to my "fire arm" related magazines and packages. We have a mail carrier back home who is anti gun (openly told me this once when delivering a package from a gun store) and tries to push her view on everyone. Any time she is delivering the mail I either don't get the magazines/letters that are fire arm related or they are damaged beyond serviceablity. My neighbors and I have complained about this many times and she has been reprimanded, but it has been going on ten years and it still happens. Mostly nowdays i have my gun and hunting stuff that is sent through USPS to a P.O. Box. Never had a problem with fedex or UPS.
Also, she did it a few times to my VFW magazines and boxes and I contacted VFW who's lawyers sent her and the post office a "nasty gram" and it has not happened since with VFW/VA related stuff. I am looking forward to when she retires/dies or gets attacked by a killer chihuahua