The Sims 3 Diesel Stuff product code

I recently purchased a couple of Sims 3 games from Origin, including the Sims 3 Diesel Stuff.  All the others worked fine and are now installed, but while installing Diesel Stuff I was asked to enter the product code received with my purchase.  The product code was not shown within the game information in my Origin account and also not in the email receipt I received after purchase.  How do I retrieve the code from Origin? Otherwise I am unable to install my game.  Any help would be much appreciated, thank you. 🙂