I have had the reverse problem. I use Amazon Prime two-day shipping fairly regularly, which requires that I specify a physical address for delivery by UPS. Occasionally, however, Amazon will decide it wants to ship by USPS and will try to send my package to my physical address which does not have postal service rather than to my Post Office Box. I tried to get Amazon to understand that they need to have an option to select the destination address based upon their choice of shipping carrier. No luck. Eventually, I settled on adding "PB ####" following the street address; my local post office usually (but not always) figures out that this is a box designator when they cannot deliver to the street address and I get the package delayed by a few days.