Dear atcharachawe,
At Yahoo!, your account safety is our top priority.
Recently, we have detected some unusual activity on your account and as a result, we've temporarily locked it for your protection. You may unlock your account immediately by logging in on a PC. If you have additional questions, please visit us at http://io.help.yahoo.com/contact/index?y=PROD_ACCT&locale=en_US&page=contact&srcContact=acct_care#voice-form to get the help you need.
Sincerely,
Your Yahoo! Customer Experience Team