We have put together a short survey to capture your feedback in terms of what BT can do when you experience home Wi-Fi issues. We would appreciate it if you could take a couple of minutes to complete a short survey. Read more from here, Fix my home Wi-Fi
If you can set up a BTID and access your MyBT you should be able to set up a BT email address.
See links how to set up a BTID and a new BT email address
If you have an account number, you can create a BTID and hence an email address but why would you want to create an ISP email address that will make a rod for your own back when you move providers? Its not the best of mail services either. Just use an ISP agnostic email address such as Gmail.