My closed account is still sending spam in Yahoo mail?
Once a Yahoo mail account is closed, you cannot send mail, but in some cases, it may appear as if you were sending spam. If you have a closed account that appears to be spam, the cause is the forgery of the email.
Fake email seems to be sent from your email address, but it is actually sent from another email account. Email providers cannot prevent their names from being forged, but if people are receiving emails from their closed email address, they can report it.