When I hit enter to log in to my account, I get a redirect to a white screen saying the page does not exist. I tried to pay over the phone, but my PIN isn't what I set it to.
Where are you clicking to log in? Try logging in from the my account login when you Google it. Otherwise here is information on public mobile payment vouchers and other alternative means of making a payment that should prove helpful to you.
Try private mode or another browser or even device.
You can also buy vouchers and use 611. Or even real time payments in a few stores.