LogicallyIronic For WA, since you still have the code, you can contact EA customer support and ask what happened to your pack. A support rep could look up the code for you and see whether, for example, you might have redeemed it on a different account.
I would strongly recommend using live chat rather than email. If you're not seeing the option, try this link:
https://help.ea.com/en/help-contact-us/?product=the-sims-3&topic=missing-game&category=manage-my-account&subcategory=find-missing-game
Make sure you're already signed into the help site and that your location on that page is set to U.S. or U.K. It's fine even if you live elsewhere.
If WA is in fact attached to a different account, you could have it merged with your current one. Seasons might be there too. Otherwise, without a code, you're out of luck.
Typically, physical copies NOT registered in the EA App don't get along with digital copies. The App will usually block access to any content it thinks you don't own. You could always try a combined install; the worst that could happen is you waste some time. This would only work for WA, at best, since you'd still need a code to install Seasons from disc.