Welcome to the Community and thanks for posting. I have moved your post to a new thread as the last thread was already marked as solved and may not get much traffic.
Sorry that you are having problems viewing your bill on BT.com.
Have you cleared your cache and cookies or tried another browser or device?
I had this problem this morning because the computer automatically filled in the wrong e-mail address, which I did not notice and that e-mail page came up. Putting the main address in took me into MyBT with no problems.
Thanks for that, I had carried out all the suggestions above without any success. I have contacted BT via their online chat and have been told it is a technical problem, they have raised a case and passed it on to another department to be resolved in the next 24 hours.
I received a call from BT this morning, they have resolved the problem and I can now view my account again.