Playable, downloaded Sims 3 expansion packs not apearing on Origin

@cassaroll_sky  In your Origin library, only the Sims 3 base icon is supposed to appear.  When you click on that icon, you should see a dropdown menu labeled More towards the bottom of the window.  Click on More and check the Expansion Packs and Stuff Packs tabs.  Are Late Night and High-End Loft Stuff listed as owned?  Specifically, does it say Installed on the button below each icon?  If so, and your packs show up in-game, then you should be fine.

The fact that your codes don't work is to be expected—you can only register them once, even to the same account.  But it's always a good idea to save them somewhere, along with the email or CD case insert they came with, in case anything ever happens to your packs.  EA has been known to make mistakes with accounts, although it's almost always easy to fix the issue by contacting customer support.

Thanks!
Unfortunately, they are not showing up on Origin using your recommended method. I doesn't show them as downloaded or installed, only the Buy option.
Is it possible for them to be registered and invisible? I don't understand how I can play with the active packs, yet not be associated with Origin or Sims 3 website. It's extremely unlikely that I made a throw away account to download them originally, considering how old the Origin and Sims account are...

@cassaroll_sky  How did you install the game?  If it's via disc, you might not need to play through Origin at all, in which case it wouldn't matter what your account said.  I'm actually not sure how Origin handles a disc install that it does govern, i.e. you're forced to launch the game through Origin but used the discs to install.

Even if you never registered your packs in Origin, you may have done so on the Sims 3 store site.  The store and Origin share information, so your codes would read as already used.  If you can't link your store and Origin accounts, or you can't figure out where your codes went in the first place, it's best to contact EA customer support to ask that someone look into things.  It would help to have photos or screenshots of the codes on hand for the chat to prove ownership.  But you're right, you'll want to sort this out to cover your bases in case you ever need to reinstall.

https://help.ea.com/en/contact-us/

Edit:  I should have added, it's worth clearing Origin's cache, in case that's the issue.

https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/

I did install though a physical disc. I cleared the cache a while ago because my game randomly crashes and that was recommended, but will try again *fingers crossed*. I will contact EA as a last resort since my previous interactions weren't successful.
Thanks for your help thus far.

If anyone stumbles upon this port with a similar issue, here's an update:
After a contacting EA, they have concluded that my games were essentially copies with fake codes. I bought these disks from a major retailer, so am not completely satisfied with this being the truth. It's too bad.
Happy gaming.