Last week though, I got caught on this one, as my phone company had a billing error and direct debited far too much from our bills account. What the! I cancelled the direct debit and decided I'm going to have to sit down and pay it myself (or schedule internet banking to send the payment) every month.
I should note that I NEVER set things up so that anyone has direct access to my bank account. I pay bills by "pushing" payments or by having them paid onto a credit card. (If they make a mistake, there will be interest charged if I get charged any. I know my rights and have never lost a challenge!) The things I automate are investments. It works like this:
Paycheck goes into checking and a fixed amount is automatically sent from checking to money market every month. Mortgage and a couple of other fixed payments are also automatically sucked out of checking. Bills that can be paid by credit card are paid by AMEX and I manually pay that bill from checking every month. Bills that cannot be paid by credit card are manually paid from checking.
I got an electric bill for over $10,000 one time due to a meter reading error on their part. My system protected me. I simply called and pointed out the error and refused to pay until it was corrected. If it were automated I would have had a problem. You always have to think about the "what if the company screws up" situation.