Can't Create New Account

I used to be a XFinity Prepaid customer, but am now an Internet Essentials customer.  My old account was deactivated and now shows as inactive, and my new Internet Essentials account is now active as of today.  I want to log in with my new account, but am only able to log in under my old account.  If I try to create a new account, I'm told that my email and phone number are already in use.  But I only have one email that I use, and one phone number.  Can the old account be deleted so I can use my email and phone number to create a new account?  Obviously, for example, I can't check my billing for the new account if I can only log into the deactivated account.  (I had to log in with my old account to post this message.)

P.S. - I did create a new login after I applied for Internet Essentials and my old account was deactivated, but logging in with those credentials brings me to my old account, even though the username is different.  I made sure the account number I saw when logging in was the old one and not the new one for my Internet Essentials account.