My wife and I recently switched to AT&T and in our first month, AT&T claimed we used 2.75 gb of data in just 14 days.
When we used Verizon we used 1.77-2.10 gb per month.
We didn't download videos or music with AT&T, so how we used that much is suspicious.
I even talked to a manager at AT&T named Ernesto and he claimed it was because of the IPhone 6. I still don't buy it as we were using the IPhone 5s before we went to AT&T.
Be on guard!!!!