because apparently you can not change you email address without having to create a whole new account according to their customer service....
When I pointed to them the fact that I have already purchased the game with my existing account their reply was nothing!!!!!
So apparently in MMO that we are supposed to play and pay for years we are not allowed to change our email address ( a need that could very likely arise for many people during the time they play the game ) without wasting our time and money we invest in this game......
edit: for people making assumptions, I have to change my internet provider from Virgin media to Sky for reason purely personal. That means I have to change my email as well