Same address two different account

When you log in, providing its the same email address, you should see the accounts you would like to select and then manage them.. If you do not see both accounts in there its likely that the two accounts are under different email addresses. In that case, whomever is responsible for that account would need to make your account an active user on their account to cancel it. 

See here for more info: https://www.xfinity.com/support/articles/primary-and-secondary-accounts

Hello user_dl7zd2 thanks so much for taking the time to reach out today here via our Xfinity Forums! This is certainly a unique situation, and we'd love to help get everything sorted out for you. 

Please send a direct message by clicking the chat icon in the upper right corner of the page, clicking on the pen and paper icon, and then entering “Xfinity Support” in the “To” section. Please include your name and address, and we can get started anytime.