I no longer have a BT email address but I am desperately trying to retrieve vitally omportant emails. Does BT help in such matters? I have tried Customer Services but that was useless. They simply didn't understand.
The short answer is no.
When an email address is deleted, you won’t be able to log into it.
For 60 days, the deleted email address can be reactivated by the BT ID account holder via MyBT. After 60 days, the contents of the mailbox will be permanently deleted and can't be recovered.