Is the area code 333 with prefix 723 (333-723-xxxx) within the U.S., Canada, or where?

I have looked on different reverse phone lookups and area code finders but cannot find anything on this. The phone number is linked to a cell phone. Any help would be appreciated.
When I was in Italy, this was the number my tour guide provided to get in touch with her in case any of us got lost or were late for the bus going to the next destination. I called the number once in Italy and she picked up.
So you all are saying she is using some sort of spoofing service so none of us on the tour knew her real number. I wonder how I could obtain such a service for my phone, if this is the case.

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