"We refund the data you don't use" is basically a way of saying "you pay by the megabyte for the data you do use" -- which is actually really great, I've been frustrated that everyone's settled on "all-you-can-eat" data as the standard, it doesn't align incentives well at all.
And they really are refunding it: if you use 1.2GB per month, it doesn't matter whether you sign up for 2, 5, or 10GB, your bill comes out exactly the same.
And they really are refunding it: if you use 1.2GB per month, it doesn't matter whether you sign up for 2, 5, or 10GB, your bill comes out exactly the same.