Trying to login but fails saying I already have an account

[Mattsta104]

I created an account and went premium on my Mac.  I have logged out of the account on my Mac and have downloaded Spotify on my Iphone.  I am now trying to LOGIN to my account on my Iphone but am getting a message saying 

"login failed"

"You've already created an account with this email address"

Is it just me ? or is this contradictory ???

I'm trying to login, and its telling me I can't because I have already created an account!  What the ???

Any help would be appreciated.  I assume I am doing something wrong.

Cheers