Your name and email and address are no doubt all over the Internet if you have signed onto any web sites or entered it into anything online.
As regards the code. When you try to log onto your email account you will see there is a "forgot log on details " link.
This generates a security code that is sent to your chosen email address or text number so that you can use it in order to get into the email account.
The scammers, who know your email address use this when they are on the phone to you. Because they have told you they will send you a BT code to prove they are genuine when you receive it you accept they are BT and happily hand the code over to them.
This then allows them access to your email account and all that that allows access to such as your bank etc.
You did the right thing to hang up.
BT will never cold call you to tell you there is a problem with your email, Internet or anything else.
