Same issue for me, I didn't see your post before I posted my issue. Thankful its not just me, but mine has been like it for about a week now and I'm due speed upgrade any time soon (maybe!) and without that page I have no timescale status!
I am also having the same issue: blank page when I login. Speed upgrade was due by end of month and I cannot check timeline. No luck getting in touch via web chat, all operators busy. It has been going on for a few days now.