Excel update screwed up my license I purchased

I purchased a new iMac in 2019 and purchased a license for Word and Excel. For some stupid reason I hit the download button on the App Store for Excel thinking it was an update. Now I can't do anything in Excel because it wants me to get a subscription to Microsoft. Word is still OK. How do I un-do that download of Excel and get my old one back with my license I purchased? I'm running macOS Big Sur V 11.2.2.