I can't get access to my game at all.

@milked83  There are potentially two problems to be addressed here.  The first is that you may not have the 64-bit version of Sims 3 on your account.  This is a common issue and can be fixed by support.  The other is that the EA Play version of Sims 3 may be blocking you from accessing the game in macOS, whether or not you have the 64-bit version.  Because EA Play is only available in Windows, so are any games that come with it, even those that include Mac versions.

For each issue, the move is to contact EA customer support.  I would strongly recommend using live chat rather than email.  If you don't see 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 signed into an EA site (this one is fine) before clicking the link and that the location in the lower-right corner of the browser window is set to U.S. or U.K.

For the EA Play issue, you only need to request that this version be removed from your account, if it's present.  For the 64-bit version, you'll need to request the "entitlement," as it's called.  If the support rep isn't helping with that, feel free to link this very long thread on the subject:

https://answers.ea.com/t5/Technical-Issues-Mac/SOLVED-64-bit-Sims-3-content-not-in-Origin-library/td-p/9653314

Finally, let me know if this doesn't work, and I'll flag your thread to someone from EA so they can take a look.