@beccahimes
No worries, it's a challenge to get it up and running for you now 🙂
The code is valid for both Mac and PC so no issue there.
Are you running any antivirus or a 3rd party firewall? If so disable them. Do the same if you're using a VPN. Also, close Origin then download and run the reset Origin tool, you can find it here - https://help.ea.com/uk/article/how-to-reset-origin-on-mac/
Once that's finished (you'll get a little pop up telling you it's done) open Origin, go back to your games library and try downloading again.
Fingers crossed......