Processes in Microsoft 365 for setting up Office apps, redeeming product keys, and activating licenses.
The simplest answer I can give you is...first remove all traces of Office from your computer. Second, log into your account on Office.com/setup and select "install from a disc" (see below) and burn the program to a disc. After you have the disc burnt, disconnect your computer from any network and install from the disc. This should work, it did for me. You may still have to call to activate, but at least you'll have it installed. Good Luck!