SCAM ! Do not fall for it. Same story as with everyone else here.
Here's how you get a quick response:
1.) Scan your "fake" invoice and email to their address (on the invoice).
2.) Let them know that you never signed up or authorized their services.
3.) Inform them you complained to the Arizona Attorney General, consumer complaint department, https://www.azag.gov/complaints/consumer
4.) FILL OUT THE COMPLAINT.
I got a response within an hour. If enough people complain, they will be investigated.