First and foremost it is very wrong to entrust huge amount of money to any web wallets. Second that's pretty big mistake that you gave to them your login details, I don't think if they will give back the bitcoin you have on that wallet. And you can reset all your login details including email you used only if you have the passphrase of your wallet. Its working as I tried it already when I used blockchain before, and it happens when my smartphone got stolen including my 2fa. And I used the 12 passphrase to recover those funds. They will ask you new email and password and they will give a new ID for logging in.