iPhone activation issues

I got a new phone and followed the instructions for activation. The new phone is all set up, and the old one has been off since I bought the new one. However, I tried to make a phone call, and it says my phone isn't activated? I looked in the settings and sure enough there's no number associated with the phone, and no data plan is listed. My old phone is still registering as the activated one for some reason. I tried iTunes and clicked "set up as new phone" but nothing happened. Does anyone know how I can activate the new phone for real (hopefully without deleting everything? It's been a couple days :/ ). Thanks!