Watching data free on non-AT&T ISP's - DirecTV

Background: I've read more than 200 post and spent a wonderful 2 hours on the phone with customer service. Maybe my question is too specific or I'm not asking it the correct way. I am using the english language. There is no answer (to my satisfaction) as of yet.

Logisitics: I have two homes very far apart. In house "A" I have a fairly new DirecTV service, two AT&T cell phones (4 on the bundled plan) and NO internet service. In house "B" there is an AT&T cell, a NON-AT&T cell (because of no AT&T service in the area) and an ISP IDSN metered service that people who remember 2400 baud dial-up would disgusted with.

Problem: I like to catch up with CNN and see who died on TWD*. So, I take my NON-AT&T cell while it's connected to my WiFi and screen cast it to watch DirecTV. I have the proper DTV app and I'm logged into my account. Oh! And I have the NFL app to catch a game or two when I'm there.

Issue: My lessor than internet friendly ISP says I blew through a month worth of data in 11 days. The only thing I used the data for was DTV. My ISP plan is for 450 gigs a month @ 50Mbs bandwidth.

Question: If DTV is suppose to be data free, where is my problem and why am I being charged for it?

Thanks to anyone that might have some insight.


This question, "Watching data free on non-AT&T ISP's," is about DirecTV channels, programming, equipment, and sports.