AT&T is shady as fuck.
Signed up for WiFi in the car for a long trip for the kids and then turned off auto-renew.
Got an email saying my service would end (as I intended) and would need to manually pay online since auto-renew was set to off.
Lo and behold, 3 days after cancellation, they go ahead and charge me anyway.
Customer Service rep basically said they do that and now that "service" is set to off so I don't get charged again.