Beginning September 29, I am not receiving texts from one ATT user who has an iPhone 5. I had made no changes since last receiving texts from this ATT user (I was still on iOS6) and the ATT user had made no changes. His device indicates the messages were delivered, but I am not receiving them. However, I am receiving texts from other ATT iPhone 5 users.
I tried turning off iMessage but that didn't fix the problem. I powered off my device, but that didn't fix the problem. I upgraded to iOS7.0.2, but that didn't fix the problem. I checked to see if I had inadvertently blocked the ATT user's number, but no numbers are blocked. I am at a total loss.
Any ideas?