Sims 4 (purchased) wont launch, suddenly asking for membership renewal.

Hi there OmniTetra​ 

If you've fully bought the game, we'll need the live support team to look over your account details and be sure the correct version is available on your account since your membership has expired- this isn't something we can look into for you over the forums as we don't have access to your account or billing details.

You can contact live support for more help on this from the site here- I'd also recommend attaching this forum conversation when you reach out there so the team has further info to reference.