You have not done anything wrong. Keep in mind that your password is case sensitive. Make sure CAPSLOCK on your computer is off (or on, depending on whether CAPSLOCK was on or off when you registered your ecoAccount). In order to log in to your ecoAccount you should type in your username and your password.
You should contact their support team, as, unfortunately, we cannot assist with this problem.
If you forgot your password you should initiate password recovery process and follow the instructions.
Go to www.ecoAccount.com and click on 'Log in to your account' button, enter the username and password you chose at registration to log in to your ecoAccount.