Verizon Data overages Nationwide

Got hit for data exceeding our 10GB on the last 2 billing cycles.  I have 6 devices 4 phones, all are Apple 6SE's  and 2 IPads.  Have had no problem with data overage for the preceding 5 years. 

I managed to get a "data log" which breaks down the data usage.  Imagine my surprise when I find devices powered off using data, despite having WIFI in my house.  Called Verizon and have been told every excuse possible for this, the phone can turn WIFI off, my WIFI must be down (I have a private, very reliable provider), I must have just used itand finally it must be an Apple problem. 

When I called Apple and asked about the phone's ability to turn off WIFI, they said that was news to them. 

When I dig deeper I find 1 device has been using data all along, despite being powered off and in a drawer and that whatever is going on started with my August bill and a dramatic increase in data usage.  It's only used for a week in May and 10 days at the end of September beginning of October. 

So after a lot of time on the phone with Verizon's more than nasty Customer Service people, I turned my phone off at 6PM last night.  Imagine my surprise when I checked my account and found that my phone was using data during the night and still isn't turned on.

Verizon can not explain this and after looking at their FB page and the incredible amount of people complaining about the same thing, I  believe this is some sort of scam from Verizon.