Post Office A$$Holes!!!!!
I was a machine mechanic for the USPS for 11 years. I can attest that the sorting machine can mangle packages in short order. Most of them get through unscathed but a few do get smashed.
There is an area at the Bulk Mail Center where all smashed and mangled packages are brought to to be pieced together, taped up and hopefully an address will still be intact, then they are put back into the system.
I lost a carrier yoke through the Post Office from an ebay seller that tried to mail me. Took a lost on that one. I only use UPS or Fedex with tracking info.