Account registration flaws

I have moved my business internet twice - now at 3rd location. Each time I have been assigned a new account number and each requires a new registration online to access and manage my account. I now cannot register for my 3rd location and 3rd account number since my 2 previous accounts are still active and associated with my 2 email addresses. I do not have a 3rd email address to use. I have searched but cannot seem to delete my 2 old accounts and free up the email addresses. Of course it is after closing hours of Comcast Business customer service - I apparently have to take a day off to stay at the computer and phone to be able to call them during their business hours? How do I delete the 2 older accounts and free up my email addresses to be able to register my current account? Also, I am paying for 75mbps speed with the new "upgraded offer" from the sales agent when I moved service but am only getting 30mbps. How can I remedy this?