Can someone help me' poor mum out

Now, my Mum, who is unfortunately around 2-thousand miles away from me has a problem. She has been buggered over by the idiots a the bt who have managed to mess up th login system on her e-mail. Now this has happened before. But my silly mother went and changed the password, and neither the old password, nor the new one work.

Thankfully my mum's shouting voice should be enough to get the blokes at BT to sort the first problem out. my problem is due to the windows 8 mail thingie she's using. It is refusing to let her change the password it uses to log into bt (I assume it's some kind of API), and is instead just defaulting to the old password. Can someone give me some clarity as to what's going on and help me out a tad.

Cheers.I