I have a friend who has an iPhone 5S with AT&T. I sent them some I messages last night that went to SMS messages. Some of them say sent another one saying not delivered. When I called her phone there are no rings it goes immediately to not excepting calls at this time. I called the phone from another number and at the exact same thing so I do not believe I'm blocked I'm wondering if their phone is broken or maybe the bill has not been paid I'm not quite sure any help would be appreciated