AT&T was pushing the e-billing and autopayment by offering a discount on the monthly rate, which supposedly was fixed. What they did not say was that they would not send itemized electronic statements, just an email stating the billing amount, along with a link to the statement on their web site. That would require logging into my wife's account, and that access is now screwed up and requires resetting.This kind of situation is precisely why I very much prefer to give my service providers payment rather than let them take it. Yes, I have to remember to do it, but it means there are no nasty surprises. They send me a PDF statement, and I pay it, without anything sneaking past me. That is worth any convenience I give up.
I have used autopayment without problems before for other fixed payments, like mortgage and loans, and the banks handled it flawlessly (although final payments required human intervention). I did not expect AT&T would fail to notify customers of rare increases (although, so far, our rate has not increased).
I would never use autopayment for utility bills that vary month to month, because major screwups can happen. The local gas company billed new tenants $8000 for seven days of service in July, because they had overestimated a prior reading and their computer misinterpreted the first real reading as the meter having gone through a full cycle rather than the previous estimate being off.