taken from https://secondlife.com/account/call_us.php:

In order recover your password, you'll need to call us.

Our customer service is available Monday thru Friday, 9am-6pm PST at:

    * 1-800-961-6851 (US and Canada)
    * (00) 800 722 00010 (UK)
    * (0011) 800 722 00010 (Australia)

For more information and numbers to other countries please refer to our support* page.

*https://secondlife.com/community/support.php