Why can't we have an alternative to DHL??

[ryo]

PO Box means "Post Office Box". It's a mailbox located inside the post office. It's used in North America for people living outside of delivery zones. The post office will hold mail and packages up to 50lbs there, then the recipient has to come pick it up.

Ah, I see.
In that case, it's understandable they won't deliver to PO boxes, considering you need to personally sign upon arrival if you receive something from overseas.
Although I doubt they actually check whether it's your signature or of that of your friend's son's dog.
So if you have a friend who can receive at their home, use their address and then just pick it up at their house for example.
Or at your office if you work at one.
There are always ways around everything.