@MeganFord1213 For the packs with no code, how did you buy them? If you went through Origin, you might never have received codes at all, as is normal for players these days. You'd need to contact EA customer support to get the keys, but that should be easy—the rep could look up your purchase info and pass along the codes.
https://help.ea.com/en/contact-us/
If you originally owned discs, the codes will be on the backs of the inserts inside the CD cases. Or, if you had the game installed previously on a different computer, you could find the codes via Terminal command. (This would work for any computer on which you have installed but haven't done a clean uninstall.)
https://bluebellflora.com/finding-your-serial-key-using-terminal/
Otherwise, EA support is the only option. Since the packs have been registered to your account, the codes will still be in their system.
For the packs that won't download, this workaround has been helpful:
https://answers.ea.com/t5/The-Sims-Mac/Sims-3-packs-not-downloading-through-Origin-mac-OS/m-p/7197851#M15258