Are you a BT Broadband customer or paying for your email through a BT Premium email account.
If you are neither of those BT are in the process of deleting non BT customer's email accounts.
If you are one f the above, you should log onto your MyBT and go to "Your Products" and then "Mail, manage". You should see your email account there and what status it is showing.
Post back with the result for further assistance.
