How do I return a sims 4 expansion pack?

Hello,

I am a noob that does not read patch notes. I just like playing games and listening to overview of videos (sometimes) but clearly I missed out on important information that would inform me that expansion packs no longer work with legacy Sims 4. It's Christmas and so I bought to play for the holiday.. only to find out it does not work! SHEESH! Now I have to wait for regular working hours for someone to help. Is there a certain number of days before it is not longer refundable? I wish there was a warning sign for it before I downloaded (through the Origins app on Mac).