I was wondering the same thing. It's more than a year since I received the "you will be transferred to BTMail soon" message or words to that effect. Still no sign of any change.
Maybe the word 'soon' has a different meaning in BT circles.
Have a look here :-
and click on "So will I still be moving to BT Mail?"
Hence a year has passed since it was suspended.
As usual there isn't any real reason give, just a stock answer which is clearly false. As I've said many times, it's time for BT to come clean what the actual issue are and why use Openwave in the first place. They are a dreadful outfit.
It's worth reading the history here :-
Once migrated to btmail, there is no going back. This is what I was told by many BT technical staff, both in India and the UK.