Xfinity arbitrarily pausing internet service without telling me that it is paused

I am enrolled in autopay but the autopay date is a few weeks after the statement is released to me. Xfinity shuts off my wifi immediately on the statement release date if I do not manually key in a payment on that same day. Checking the xfinity app while on data tells me that the internet is on but it is very clear that no devices can connect. As soon as I pay manually, the service is back in a few minutes. 

How can I set up auto payments that don't leave me without service for half the month? Is it legal to cut off my service before the due date to get me to pay faster?