Missing Expansion Packs – The Sims 4

ChristinaMich23​  This isn't EA help, so I can't help you directly.  Even the EA community managers can't make changes to account details.  But what I would suggest is checking your various email inboxes for any e-receipts or other proof of purchase.  If you find that, you can take the info to EA customer support for help, or just try signing in with that particular email address.

If you think you've found the correct account, but the content doesn't load, check your order history on ea.com.  It's possible some transactions were rejected or caught processing after they seemed to work.

Without any proof of purchase or record of the transaction, there's nothing even EA customer support can do, so you'll need to find that somehow.  The game's program files don't contain any information about the account that installed the content.