@emzy190516 What exactly has happened? It would be useful to know precisely what you're experiencing right now, as your comment could refer to several different relatively common issues.
If you already registered your codes to an account sometime before now, you don't need to do so again, and in fact Origin will not allow the codes to be registered more than once, even to the same account. So if you want to redownload the game, you need to use the same account to which the codes are registered.
Sometimes, Origin itself can act up and not recognize that you own particular packs, even when you do. You can try to clear Origin's cache, or even uninstall and reinstall Origin only—this will not affect your installed games.
If you can't remember your password for the original account, there should be a way to reset it. If you can't remember your username, you should contact EA customer support. Someone there can help you reset your account details. Click on the "Help Center" link at the bottom of the page and select the options that fit your problem.
If you never registered the codes but believe that you're the original owner of the games, contact EA with as much proof of purchase as you can find (receipts, email confirmation, if you have discs then photos of the discs, cases, inserts and jackets might be helpful). There's no guarantee, but an advisor may be willing to issue you new codes so that you can download the game from Origin.
If you bought the games secondhand, then you're probably out of luck. Unfortunately, EA does not allow transfer of ownership of a game or pack from one account to another.
@ianswoman The way you're supposed to get Dragon Valley in your game is that you redeem your code either in Origin or the (more reliable) Sims 3 store (https://store.thesims3.com/), and then you download it specifically from the store, not from Origin. If you've ever downloaded it before, it should be listed in your purchase history once you login to your account at the store site. But as long as your code is registered to the account you're using, you should be able to get it for free. Once you've signed in, click the "worlds" link on the left of your screen and you'll see a list of all the available worlds. On the Dragon Valley page, you should see a green download button.
Keep in mind that once you download the world, you still have to use the launcher to install it in your game. If you can't download DV at all, if it's not showing up in the launcher, or if once installed you can't select it in the game's Main Menu, please post back here describing exactly where the process is going wrong.
Unfortunately EA has outsourced their call center to another country, and they obviously don't feel they need to treat their customers with much respect anymore. I guess they don't think we'll ever get smart and form a class action lawsuit for their mishandling our accounts. Today, that very same call center wanted all my diagnostic info for my computer and then said they would send me an email in a couple of days to fix a glitch in my computer that was supposedly interfering with my Sims game that they later admitted to not being able to fix at all. I asked them what exactly were they going to do on my computer anyway if they didn't really have a solution. Their answer? "Well uh..." I adamantly said no and to stay on the phone with me until the problem was resolved. Three different people got on the phone with me and asked me for the same info on just exactly what was going wrong with the game. There was no real communication there. I even went so far as to attach a video recording of the glitch and they told me they couldn't open that kind of file in their country. What kind of call center hired by a huge company like EA supposedly is, doesn't have the world-wide resources to open a simple file!? So I just demanded a refund or I would call my state's national security office and start asking them to look into why another country wants our computer's diagnostic info right down to the drivers and their build numbers. That can't really be necessary. Then they gave my my refund. So I promised I would buy another game for my Sims as a peace offering for them keeping ME on the phone with them for over two hours. And guess what I got. I ordered the Monte Vista world, got the receipt in my email showing I had received the download of Monte Vista, they got their money out my pay pal account: and they gave me a code that redeemed some two thousand Sim points instead. On their EA site, their billing info doesn't even show they gave me anything. And the Sim points never appeared either. But they sure got their money. And now I can't reach them anymore. What a coincidence. Time to be careful. This monster EA/Origin conglomerate doesn't seem to care about their members anymore. Whenever you do reach someone from one of their centers, take names and document the conversations. And find more dissatisfied customers. See if they have experienced anything similar or suspicious. And speak out! This isn't just a game anymore.
This is going to sound a bit dumb, but I made this mistake so others may have too.
I logged into my (only) Origin account and saw that I only had Sims 3 base game (but not installed), and none of my 6 expansion packs.
I started downloading it and while I was doing that, I tried to add my expansion packs using their codes, and it wouldn't let me, saying they'd already been used. So I came on here - didn't find an answer.
BUT, while I was reinstalling the base game, it automatically prompted me asking if I would like to add each expansion pack to the download queue. It automatically recognised that I had those games, but it didn't show them as game tiles in Origin.
Anyways, I guess (hope) this may help for people who can see their base game in Origin but none of their expansions/stuff packs.
@bumboompap If you've already entered your code once, you'll get that message, even in the same account. But your content should already appear in your Origin library. Sign in and then click the TS3 base game icon in your game library. Click the dropdown menu labeled More and select Expansion Packs (or Stuff Packs), then scroll through the list to find your owned packs. You can install them from here.