If you cannot get rid of your account for Yahoo and want to delete it, follow the screens below.
Click and follow this link Delete Yahoo Account then enter your details to login.
Read the terms and conditions and scroll to the bottom of the page.
Click the Continue delete my account button at the bottom of the page.
A pop-up window will appear asking “Are you sure you want to terminate your Yahoo Account?” Once you are sure, click the Yes, terminate this account button.
A message will appear to acknowledge that “Your account has been deactivated and scheduled for deletion”. Click Got it to complete the process.
Once done, your previous account will now be in the queue for deletion and you can create a new account.