I have just put in all my card details and everything to purchase S2, but for some reason I'm still a demo racer

the game wont accept my username or password and when i check on the site it says i havent paid and dont have the license

anyone know what happened?

The only people that would beable to tell you would be your bank and/or the developers. You can contact the developers directly here:
http://www.lfs.net/?page=mailus

cheers, I have emailed them, just waiting for some feedback now