Why won't my new iPhone 6 (AT&T) send or receive texts/calls?

I activated it two hours ago and backed it up with the data and phone number from my old iPhone 4. Both phones now read AT&T and show cellular signal and data in the top left hand corner. But when you text or call my phone number, the iPhone 4 receives it. Why won't my new phone receive it?

You need to turn the old phone off, so the new phone can finish the activation process. If the old phone has a SIM card in it, take it out until the new phone starts reviving text, in fact you will not be able to use the old Sim card once the new one starts receiving text.