Best as I can figure you have two options:
Take in on the chin....act daft say you bought the watch in the Netherlands - for reasonable money (which you will have to invent a plausible scenario for) and you unwittingly sent it to USA for mods/repair without giving thought to this problem, and see how it goes. Best case, they smile and let you have the watch....worst case they hit you for duty (pay or forfeit the watch).
or
Contact them and say you don't know anything about it, whoever sent it has mixed you up with someone else, and SUGGEST they return it.
No easy choice I'm afraid
.