Thank you all very for your help. I have sent a message asking for the association of my accounts to the Cie Games http://www.ciegames.com/racing-rivals/support ... and wrote in the Contact Us. Hope I hit right point of contact.
Is it possible to delete my old account and start all over again with new account? I have tried but every time I started the game, it says Game Center Mismatch... Load User or Keep Playing. And I really want this message not to appear again with my new account