Unlocked iPhone 6s bought in Germany in Verizon network?

Hi all,

my wife and I recently moved from Germany to New York - she bought her iPhone 6s in a German Apple store while I bought my iPhone 6s in a Apple store here in New York.

I bought two Verizon pre-paid SIM cards but it appears that it doesn't work with my wife's iPhone. It's saying no service and the Verizon hotline told me that her iPhone (IMEI) isn't in their data base due to the fact that it's bought in Germany and that there is no way to add it. Basically that would mean to either buy a new phone (not an option) or to go to AT&T.

Does anyone can confirm whether there is really no way to add a foreign iPhone to Verizon data base? Sounds ridiculous to me to block "non-US" iPhone even though it's cable for CDMA.

Thanks