Tell HN: Comcast says they slow service for late payers

Apparently my autopay wasn't working, I got a bill in the mail, and when I called in the customer service agent told me Comcast was deliberately slowing my access because I was late. I looked through their agreement and nothing jumped out at me that seemed to authorize this, but I'm not a lawyer either. Is this just a line to get me to pay, or is this actually happening?