I've asked a Comcast employee to help you. You should expect a reply in this thread.
Hello Loretta0642, I can get your old account removed from your username. First I will need to verify your account information, can you please send me a private message with your full name, street address, and your new account number by clicking on my name (ComcatsAmir) and then "private message me"?
When I login to the xfinity web site it shows the wrong account number.
I switched from Comcast business to xfinity (3 weeks ago) and it still links my old account.