PLEASE Help!! The Sims 3 Serial number~?

I just returned home after buying my game. When I try to register it, it says that the serial number has already been registered?

even though during the registration process it said I couldn't register, I got an email saying "Thank You for Registering". Odd and a little aggravating, but the end result is what I had wanted so all is well.

I Did repeat and do many things ,But it isn't working >____<

Please Help me ,I Dont know what to do to make it work anymore.