If Office Home 2024 was purchased, the product key is a one-time redeem code. After redemption, installation should be done from the Microsoft account that redeemed it, not by redeeming the key again.
Try this end-to-end path on the MacBook Air:
- Sign in at https://account.microsoft.com/services/ with the same Microsoft account used for the purchase or redemption.
- Check whether the product shown there is Office Home 2024 or Office Home and Student 2021.
- If Office Home 2024 appears, select Install from that page and run that installer.
- If older Office apps are still affecting the install, remove the Mac apps first:
- Close Word, Excel, PowerPoint, and Outlook.
- Open Finder > Applications.
- Locate the Office apps, control-click each one, and choose Move to Trash.
- Download and install again from the Microsoft account page.
- After installation, open an Office app and sign in with the same Microsoft account used for the purchase to activate it.
If the installer file is not behaving correctly on Mac:
- Check Downloads or in Safari use View > Show Downloads.
- If the
.pkg file downloaded but will not open, move it from Downloads to the desktop and double-click it.
- If it still fails, delete the installer
.pkg, empty Trash, then download again using Safari from the Microsoft 365 apps page and use Install apps.
For a refund, contact Microsoft support. If the purchase was made through the Apple App Store, the refund must be handled by Apple Support.