I called them a week ago with a seperate issue. Basically when uploading builds I can not select the export compliance, I managed to submit it with my plist. Now I am having the same issues you are having when selecting My Apps or Users and Roles.
They never gave me a resolution to the other issue other than that there dev team was looking into it. I even provided the console logs from my browser showing it was an issue with there backend api. This is just getting to the point where Apple is extremely unreliable and unhelpful. They're costing me, and my company money at this point. We've got angry clients, upset developers, and now people requesting refunds.
Looking like legal action may have to be taken since we're looking at weeks of unannounced downtime.