My son has an iPod touch 4th gen. My mother in-law has a new iPhone. He logged into his iTunes account with his grandmother's phone so he could download a song for her. After that, she began receiving his facetime messages. I removed his email address from her iPhone and that stopped. But now, her phone number is displayed in his settings/message and setting/facetime under send & receive/you can be reached at. How do I delete her number?
Using the device attached to the phone number, make sure you're not on wifi and that you are using the network to which your number is registered. Turn off iMessage in the messages settings. That should do it.