Duplicate Game Accounts (how to delete duplicate/extra game login)

I am playing the game Ark of War by Seven Pirates and I had the game linked to my iPhone and my iPad, but today my iPad logged me out and created a new account for the same game.

How can I delete the new account from the game center and access my old account?

The game only gives me the option to login using the game center, so I cannot recover my old account using my email.

Please help.