Register a complaint for UK large business & public sector customers

I’m not a UK large business & public sector customer. So what am I doing in this section of the website?

Why does the site keep asking me to log in and seemingly being unable to decide if my authentication details are correct or not?

Why can’t I just view my private line phone bill?

Have BT been “enhancing” their website and made a pigs ear of it?

Is BT going to expect their customers to think it’s their fault to hide any lapses in their apparent professionalism as many companies usually do in these situations?

Any ideas?

Something to say?