I have been also affected by this issue for almost a month. My iPhone7 has been having this issue since I transferred the AT&T line from my iPhone6S:
- went to an Apple store and one of the "geniuses" told me to go and fix the issue with AT&T
- went to AT&T and they reset network settings and change the sim card for a new one and (after verifying it didn't solved the problem) they sent me back to the Apple Store because the issue was with the device.
- back in the apple store a different "genius" told me this time that "Apple is aware of the issue and is working on a software update" referring I suppose to the recent 10.0.3 version, which evidently I already tested and as expected it didn't work.
It's really disappointing and frustrating to see how, in every Apple Store, the "geniuses" act with such a fake surprised face when you explain this problem to them, like it's something new!
It's completely unacceptable that the store employees keep treating every customer like we were idiots or uneducated.
I've tried everything that a civilize citizen could do before loosing all kind of respect for a company that is just living in a bubble of fame.