Do you have any of your old emails from them as it includes your identifier at the bottom? If not you could try send a small amount to one of the addresses if you had email notifications turned on as it'll send you an email notifying you of the payment.
There is less chance to happen if this feature existed already when he made those accounts.To OP its always have an email since it is an account from blockchain, try to remember the email you used because if you don't have the recovery phrase/seed of the wallet and if you can't remember the email then there's no chance to recover it. If you remember the email address you can try to follow what @Skarner21 said above.
