@simlishlol
Hm, I'm a Safari user too, and it works for me after updating Flash and deleting cookies and browser data.
My menus are in Swedish, but I'll try to explain where I found the menu to delete cookies:
With Safari open, go to "Safari" - "Settings" and press the button on the top of this menu (it looks like a shadow outline of a person) it should be called something like "integrity protection" Haha, at least, that's the straight up swedish translation
This is where you can delete cookies for websites.
After I did that, I also deleted some saved passwords and stuff in the "Autofill" menu.
I also searched through my browser history for anything related to Sims and deleted all pages that were connected to the TS3 site.
This was all done on a Macintosh, I'm not sure if you are a PC user or not. If you aren't, I could tell you the shortkeys for doing all these things
Good luck!