Forum Discussion
390e7ae4dd998946, Hello I think you might find a fix to your issue in this forum.
https://forums.ea.com/discussions/the-sims-3-technical-issues-en/registration-and-pre-order-incentives-knowledge-base--updated-1st-page-10813-ple/388608/replies/388629
I will just paste the part relevant to you in this comment just incase you don't want scroll through the forum. (However if the code doesn't work or etc, I suggest you look at the forum for further guidance as I have not included that part.)
However there is also another part of thesims3.com where you can redeem the code if you don't get the url for it: https://store.thesims3.com/myAccount.html it will ask you to log in and then click on "Redeem a code". (You can use this link instead to try to redeem your 16-digit code)
After you redeem the code, you can go to your purchase history: https://store.thesims3.com/purchaseHistory.html and you will see the item there. (This is a direct link to your purchase history but once you log in you can probably access from the myAccount panel)
Note: depending on the size of the purchase history, you will have to probably wait around 10 minutes.