Lost access to The Sims 3 store account

@NewDrFeelgood  You'll need to go through the EA customer support account recovery process.

https://help.ea.com/en/help/account/im-locked-out-of-my-ea-account/

If you have e-receipts for your old purchases, or any other proof of ownership, you can upload that when you eventually submit the help request.  For example, if you still have some old discs, take a photo for each one showing the disc, its case, and the product code (clearly readable).