No someone isn't scamming AT&T. AT&T are the roaches in this pudding.So AT&T took over the billing for Directv a few months ago and I already paid one late charge before I figured out what was going on. They really want you to give them a credit card or bank account so they can avoid all that messy paper and postage (and incidentally take whatever they want whenever they want).
Here's the gimmick (using today's bill):
4/26/19 - Received bill
4/13/19 - Official Bill "Issue" date
5/06/19 - Bill due date
But the bill return slip has a barely legible quibble that says the payment may take 7 days to post.
Bottom line: you've got three days to get the check to them if you want to be sure to avoid late charges.
Their response will be "But we sent you an email a week ago, you could have paid on-line and avoided all this unpleasantness."
Like I would trust them with my credit card or bank account after this cr*p.