Return iPhone purchased in Italy that won’t work in U.S.

I purchased an iphone 16pro at the Apple Store in Rome, Italy because my previous phone was stolen while I was there. When I returned to the U.S., my cellular carrier, Verizon, told me they do not support international versions past the 15pro max —note that I called Verizon before I bought the new phone and was told that as long as the phone was factory unlocked, I would be able to use it. The apple sales rep assured me that the phone was unlocked (and it was, as it has an e-sim card). I would like to return the phone I bought in Italy since it will not work in the US with my carrier. How do I do this? I bought the phone 7 days ago. I cannot travel to the store in Italy to return, so would be happy to ship it.