You can easily request a My EMS account via the My EMS page on the EMS website.

After you have entered your e-mail address you will receive an e-mail with your details as known to us. Check your customer details and, if necessary, adjust them securely using your connection number, postcode and the last 4 digits of your IBAN. 

After you have checked and confirmed your details you will receive a registration e-mail for My EMS.