First of all go to
https://edit.yahoo.com/forgotroot?do...rtner=&intl=us
Pick your account has been compromised, fill in your original data to see if yahoo recognize the data.
Fill out a report details your incident below..
Yahoo! Help Form
or Mail
cc-advoc@yahoo-inc.com or
mail@cc.yahoo-inc.com
IF that does not work, you will need to contact yahoo customer care by phone.
Customer Care Accounts Dpt -
1-408-349-1572
AT & T Yahoo DSL Users -
1-877-722-3755
(unverified) -
866-562-7219 or 408-349-3300
Yahoo Personal Email -
866-492-4664
Yahoo Small Business -
866-562-7219
This infomation may be dated so expect it to be limited.