I have some companies call me from  different numbers, different states but it's the same outfit. They've even used people's names to get you to pick up the phone. Like Emily and Nate, which is a daughter and one of her son's names.

http://cnac.ca/data/ac873.htm indicates "NPA 873 will serve the same geographic region as the existing 819 in Québec (See Planning Letter PL-NANP-405). Central Office (NXX) Codes may be assigned after December 01, 2012, however, assigned codes cannot be activated in the PSTN prior to June 01, 2013."

There are therefore no legit +1-873- numbers at the current time; all that appears in the official listing of telephone exchanges are the standard reservations of test numbers (958-, 959-), information (x11, 555-), local, adjacent or proposed area codes (819-, 613-...) and assorted special numbers such as 410- (seven-digit regional tollfree) or 976- (pay-per-call ripoff numbers) in an otherwise vacant area code.

If you receive a call from area code +1-873 prior to 2013? It's bogus. Don't even pick up the 'phone.