On a trip from Guam to Japan, I decided to save myself some trouble and have a bag mailed back to the base in Japan from PostNet in Tamuning. It was a duffle bag with some snorkeling gear, books, and other items.
They told me that I didn't need them to package it - the Post Office would accept it as it was. I went with their advice and asked them to mail it Priority Mail with insurance.
Weeks went by but no package arrived. I tried to call PostNet, but no one answered. Finally, I got them.
They assured me it was sent. After numerous calls and emails, they went to the Post Office to check. The item was still there. They asked if I wanted it mailed.
Duh.