Uplay is not accepting my email

I had bought Assassins creed 3 a few months back, and now i finally got around to installing it. So, after the installation, i was asked to create a UPlay account. So i did. When i logged in, i had to install some updates after giving my cd key. I later restarted my PC. When i attempted to log in, it claimed that my email was wrong. I then made another account. When i tried to play the game, i gave my cd key. But it said that it was in uce When i used the password recovery system, it said that this email is not in my records! Does this mean that i can't play a game which i have already bought? Please help people, i really need some advice. If by chance there is a way to link these two accounts please tell.