siri cannot place a phone call or text

I have a brand new iphone 6s with iOS 9.2.1. When I use a headset or press the home button and tell Siri to call a contact, the response I get is "Calling Contact Name" (as expected) but then after a short wait I am told "Uh oh...I can't make your phone call."

When I try to text someone, I say "Text Contact Name" and the response is "Sorry, I don't see 'Contact Name' in your contacts. Can you try again?"

I tried turning Siri off, rebooting the phone, and then turning it back on. I am then able to use the above voice commands once or twice before I start getting the error again. The same thing happens when I reset the network settings. This evening I even tried erasing all content & settings (Settings --> General --> Reset) and had the same problem.

I previously had an iphone 6 and never had an issue. I've had this phone about a week and I'm completely frustrated.

Any help or advise would be greatly appreciated.