SiegeWeapon Great to hear, and thanks for all the extra info. I'm sure you won't be the only one who has to jump through these extra hoops.
Moose70 Does your computer run Windows or macOS? If you have a Mac, please use this thread:
The Sims 3 Mac Error Downloading Content | EA Forums - 11137978
If your computer runs Windows, are you getting the HTTP Status 400 error in the original post? The "Error downloading content" issue has multiple causes, so I don't know whether the steps above would help if you don't also have the launcher error. But you can try them anyway.