ErikaEmmaS Try manually removing and reinstalling the pack. Make sure the EA App is closed and the EABackgroundService is NOT running in the Task Manager. Open [install location]\The Sims 4 and delete the EP17 folder directly inside. Then clear the App's cache:
https://help.ea.com/en-us/help/faq/clear-cache-to-fix-problems-with-your-games/
And download the pack again. Please test first in a new save, and see whether the pack loads.
If this doesn't help, and you bought the pack directly from EA, please go to ea.com, sign in, open Account Settings > Order History, and let me know the status of the order: Completed, Processing, or Failed. If you didn't buy from EA, please list the retailer.
