We got a call from our UPS driver Antony, a regular visitor, so we know his number and his voice. He confirmed which package it was and told us to pay the duty/VAT online (we were expecting to pay due to the value of an order of technical items). We logged on to the UPS website (not from a link), used our tracking number which we had received from the vendor, not UPS, when they dispatched, paid the outstanding amount, got a code as a result that we passed to Antony, and he then was able to plug that code into his handheld device, and get permission to deliver the expected package. Good system, works... If I was at all unsure I think I would run full tracking on the airwaybill number to check that the package route/size/weight was as expected from the vendor location before paying.