Here are some useful links to help you:
My BT gives you access to view your bill, monitor your usage and manage your extras such as BT Cloud, BT Wi-fi and more. To log in to My BT, you’ll need your BT ID (your username and password).
BT Email addresses end in @btinternet.com, @btopenworld.com or @talk21.com.
If you're using BT Yahoo Mail and you've forgotten your log in details, the primary account holder will need to reset it for you.
To maintain the security of your email account, we recommend that you change your password regularly.
To make changes to your hub, you’ll need to log in to the Hub Manager with a password.
It's important to keep your passwords safe and secure.
If you still can't log in, please get in touch.