Okay, so 3 days ago I upgraded from my HTC Thunderbolt to an iPhone 5. Two days after that I received a message saying that I have used 75% of my data allowance for the month. Early this morning, I received another message saying I have used 90 % of my data allowance for the month. There's hardly ever a time when I'm NOT connected to WiFi. And I really don't use the iPhone any more than I used the other phone, so why is this happening?!