Billing & Insurance Northern Arizona Healthcare. Health (2 days ago) Or walk into the Central Billing Office to speak with a patient service representative in person. Fort Valley Shopping Center 1000 N. Humphreys St. Ste. 130 Flagstaff, AZ 86001 Hours: Monday through Thursday, 8 a.m. to 4:30 p.m. and Friday, 8 a.m. to noon, MST.We're closed on major holidays..