I have same issue today. im sure 100% my password correct. i was trying copy and paste, writing one by one letters, none working.
and shit i think will lost my coin inside.
In this case your only choice is use your 12 passphrase you get from blockchain.info to take back your coins there, dont expect that support will help you with this matter. Once you recover your wallet with those passphrase you will ask with new email, password and they give you new login id.