Account is locked out for an unpaid invoice that doesn't exist

My last two posts on this were closed without being resolved. My account is unavailable because it says I have an unpaid invoice. I have no unpaid invoice. My page clearly shows that I have 10,000 credits available, but I am blocked from using anything. I am fully paid on your top tier subscription and yet I am locked out of my account. Please fix immediately or give an explanation why not.