a complain about poloniex service, here : https://bitcointalk.org/index.php?topic=701535.0 maybe you can give us explanation why signed message from withdrawal address was refused? i think that is the better way to prove our account
In addition to this, Poloniex should provide the 2FA auth-key while setting it up, so users can recover their 2FA in cases like this. So many other sites do this.