brand new iP12, iMessages not sent or received

Verizon told me that once the new phone was turned on, my old iP7 would not make or receive calls. However, the messages coming in are only going to the iP7 (which I have now turned off) and outgoing messages, after turning off the old phone, do not get delivered. They show up in a green bubble. Apple support doc says:

If you see a green message bubble instead of a blue one, then that message was sent using MMS/SMS instead of iMessage. There are several reasons for this:

• The person that you sent the message to doesn't have an Apple device.
• iMessage is turned off on your device or on your recipient’s device. To check if iMessage is turned on for your device, go to Settings > Messages > iMessage.
• iMessage is temporarily unavailable on your device or on your recipient’s device.
• 
  

But none of this is true. I have checked that iMessage is on, my new phone was activated with data transferred from my old phone so all the date should be accurate.

iMessages from my old phone, before I turned it off, seemed to go through and new messages were received.

Any suggestions? TIA