Email login not working

My dad has had a trading 212 account for a while. The other day it logged him out and now is saying there is no account with that email. How can we get his account back I.e using his NI number. We are concerned someone has stolen his account and changed the email or what has happened we need help getting on to this account again.

A post was merged into an existing topic: locked out of account (for a friend)