Please note that losing your smartphone (and a backup of your secret key) means you will not be able to change your payout address. Two-factor authentication (2FA) cannot be deactivated without access to your smartphone.
You can deactivate two-factor authentication in the Settings -> Security page by entering a valid one-time password.
Alternatively, if you do not have access to your authentication software, you can disable your OTP protection by sending us a message signed by your wallet.