Screenshots below would show 3BBs message when payment due/overdue up to 1 month (in TH and EN, it's called 'soft warning'), the third pic is the login-page you reach after pressing 'Click', by that time your browser/internet-connection is back to normal.
When the first message pops up it cuts through whatever connection is active eg. VLC radio-streaming and the likes, not only browsing ... I should know, my landlady is permanently 1 month late, so these friendly reminders pop up every couple of days.
Now, I just have to keep an eye on her not forgetting the always already belated payments before she hits 2nd month overdue, 'cause then it gets locked with a 'hard warning' and you'll only get it back by forking over 2 due payments!