I thought that they work in 2 x ways.
1] You want to keep your private address private so you buy/rent a PO box address that people send things to but they end up at your 'real' address.
2] The items are sent to a PO box depot where the company signs for mail on behalf of you and you go and pick up.
Maybe your company has option no 1 and wasn't in???
If it has a face - Eat It.