UPS official policy says they won't deliver without collecting the payment (though they can't verify the payment is valid) but in reality sometimes drivers do it anyway. UPS doesn't really have a procedure in their system for handling this or if they do most employees have no clue.
The best bet is to take it to a service center and talk to a manager there. Let them know you refused COD (or the package was sent unsolicited) and that you are refusing delivery. Tossing it on your doorstep does not count as accepting the delivery, they just do that because it is cheaper for them.
If you want to game the system sign up for MyUPS so you get advance notice of all deliveries to you. Then when these unknown packages show up bound for you reject them immediately. That goes into the computer sorting system and can often get the package pulled before it even reaches your local service center.
Unless processing fees are limited by law, shipping companies gladly pay customs fees at a border so they can then collect more money from the recipient. Whether or not they demand COD or ever deliver that package, they want that money.
I recently got a notification for a package that required some like €1 in customs plus €12 processing fees. With no info on what the package actually was. I found the whole thing rather ridiculous.
The best bet is to take it to a service center and talk to a manager there. Let them know you refused COD (or the package was sent unsolicited) and that you are refusing delivery. Tossing it on your doorstep does not count as accepting the delivery, they just do that because it is cheaper for them.
If you want to game the system sign up for MyUPS so you get advance notice of all deliveries to you. Then when these unknown packages show up bound for you reject them immediately. That goes into the computer sorting system and can often get the package pulled before it even reaches your local service center.