I may be remembering this incorrectly, but I have the distinct impression that...

1.) I signed up to pay my phone bill online.
2.) I paid the month's bill.
3.) I tried to make the payment recurring.
4.) Was told that I couldn't set up recurring payments without a balance.

Came back this month to pay.

1.) I set up recurring payments.
2.) Immediately upon finishing, I was told I had to pay this month's bill via some other method.

Smooth.

Whoever's programming AT&T's website could stand to read About Face by Alan Cooper. That version is a very new reprint, but any previous version for $5 shipped should work just about as well.