I downloaded this Catalina OS update to this 2013 Mac Book Pro, then it told me that my MS Excel needed to be updated. So, I went with this Mac Book Pro online to the Apple App Store and bought the newest recommended MS Excel … but I CANNOT DOWNLOAD IT to this 2013 Mac Book Pro. Oh, and I DO NOT use the Cloud. WHY CAN'T I DOWNLOAD WHAT I JUST BOUGHT AT THE APPLE APP STORE?????