how to redownload my game from origin?

I tried but my code has already been used and i got the sims 4 with 2 stuff packs

A while ago i downloaded the sims supernatural expansion pack on a separate computer. when i re-downloaded origin on this computer all of my games downloaded automatically,except for the sims 3 supernatural expansion pack, so, i went to do it manually, but it says i need to buy it again. please help i really want it back, 

@Reeselh07  It doesn't matter that you downloaded Supernatural on a different computer.  What does matter is if you never registered it, or you registered it to a different account.  In the first case, as long as you still have the code for the pack, you can add it to your account now.  In the second case, you'd need to contact EA customer support and ask that the account with Supernatural on it be merged with your main one.

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

You can also contact support if you're not sure what happened to the pack or its code, but you'll need to be able to demonstrate ownership in some way.  For example, show the pack in your Origin purchase history, or take a picture of the disc, case, and insert with the code printed on the back.  You can upload these images directly to a live chat session.

@izzygould12345  Try clearing Origin's cache (Windows) or running the Origin reset tool (macOS).

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

https://help.ea.com/en-us/help/origin/origin/how-to-reset-origin-on-mac/

Restart your computer afterwards.  Open your Origin game library, click on the Sims 3 icon, select More > Expansion Packs (it's below the last played date), and scroll through the list.  What do the orange buttons say on the expansions you've bought?  If they say Download, go ahead and click to download.  If they say installed, check your in-game content to see whether they're installed.

If one or more packs are listed as installed but don't show in-game, try repairing the game in Origin: right-click on the Sims 3 icon in your Origin ilbrary and select Repair.  Then restart your computer and check again.

If one or more packs are still missing after the repair, or if Origin is telling you to buy a pack you already own, you'll need to contact EA customer support for help.  Although phone calls are unavaliable right now, live chat is open from 9 am to midnight.

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

I’m having the same problem, I’m using the right account and everything. I go to my games with the disc in

and when I go to put in the product code to hopefully redownload it. It just tells me this code has been used

@SmolBunnYummy  The code probably already has been used, by you, the last time you installed the game.  Does Sims 3 appear in your Origin library?  If so, you can just download it directly from there rather than needing to use the disc.