UPS Mailbox question

I have a delivery to arrive that was already shipped. I didn’t realize that it would be shipped without my notification and it’s expected to arrive tomorrow.

Here’s the problem: I expected to pay by credit card. They marked COD, which is fine with me, however, I have a UPS mailbox which it’s being shipped to.
Can I drop off a money order tonight and let them know the issue so that it will be delivered?

Does UPS have a policy with their mailboxes regarding this?