How do I get live tech support? Can't activate Excel 2019 on my MacOS 10.14.6 box.

a) Ten days ago, my computer — which had Excel installed, activated, and running on it — developed issues. I keep a bootable backup and also a backup computer (same make and model but 1/4 sized SSD) so I booted from the backup while putting the primary computer in the shop. Excel came up on the aux computer just fine but said I needed to activate it.

b) From within Excel, attempting to activate would result in "There was an error while attempting to connect to the activation server". Somehow I managed to Google a link to online (i.e., web-based) activation and eventually managed to get it to go through although it kept taking me to a page saying "You have reached a page that is not normally shown. Microsoft will never ask you to copy or share this URL".

c) The shop told me the computer had permanent hardware probs so I located a refurbished one and ordered an exact replacement for the primary computer. It arrived, I ran the backup software in reverse and am now booted from my restored environment, but once again Excel is not activated on this computer. Same symptoms as before but this time I can't get activated on web-based activation — I keep getting "The request is blocked" or that "you have reached a page that is not normally shown".

d) And I can't get a live person on the phone, or on chat! I get the AI / automated system that tells me to activate Excel 2019 I should go to that microsoft support page I've been spending all this time on.