Hi, we just activated an iPhone 5S for our son last week and it is part of the family plan with shared data/texting etc. Calls and the internet work fine. Texting does not. He is unable to send or receive texts (to and from both iOS and Android devices). We have made sure he is connected to the wireless or has data service, that in Settings > Messages iMessage is set to MMS. Finally, we restarted the phone. No luck. Please help.