E-mail exist but still able to create new account

[Genius]

I have a strange problem and not sure where to start from

 

I am able to create an account with no problems..

 

Then when i create another user account using the same e-mail address i am able to do that aswelll... BUT that is wrong.

 

I need each user to have a unique e-mail address, if the e-mail exists then the system should say that the e-mail is already registered and you need to use a different e-mail address..

 

Please could someone assist me in the right direction in validating the e-mail account..

 

many thanks