De acordo com o site deles , há quatro etapas a seguir:
1) Attempt to login through the LastPass website at https://lastpass.com/. If you are able to login via the website but not via the plugin, this is likely a problem with the LastPass browser add-on, in which case you should report the problem to us directly.
2) If you cannot login through the website, try the password hint that you setup for yourself when you created your LastPass account. The password hint is not your Master Password.
3) If the password hint doesn't help you, go to the account recovery page to activate your local One Time Password and recover your account. Follow the instructions there - if the first computer on which you attempt access doesn't work, try the same process on any other computer on which you have previously accessed your LastPass account.
4) If at this point you have failed to remember your password, your account hint didn't jog your memory, and you've tried the password recovery on every machine you've logged into, your only recourse is to delete your account and start over.
Parece que você fez os dois primeiros. A terceira opção de alguma forma permite que você obtenha uma senha local temporária. Se isso não funcionar, a situação não parece boa.