It used to be the case that, when my monthly data allowance was running low for the month, I could turn off cellular data and I would still receive and be able to send SMS messages, but recently that is not the case. I am not an iMesssages user, which I have disabled on both my iPad Air and iPhone 5. I have also disabled Messages in Mavericks on my Macbook Air. So this is confusing since obviously sms messages should not need cellular data to be sent. And just to be clear, I am not trying to send photos or anything else. I've been pretty pissed at the way Apple's screwed up this entire service, through all three iterations I have owned of the iPhone, but I don't think I've had this problem before. Usually the culprit is iMessages, but I don't think it can be blamed this time. Any ideas?