My Yahoo a/c has been hacked even my secret questions r changed

Hello,


Some miscrant has hacked my yahoo account and has also changed my secret question, further has been sending emails to all my contact list asking for money by baking a false story. Can you please advise me what steps should be taken to recover the same as I have several confidential stuffs in the mailbox which I am afraid that may be misused by unknown person.

Appreciate your attention in this regards.

Regards
Shree