A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
Hi Anna,
How confident you went to legitimate Microsoft support and not a site impersonating Microsoft? You didn't tell us where you actually went for support, so we have no way to confirm the site's legitimacy.
Thinking about whether your Mac was compromised, you made no mention of being asked to grant permissions other than for installing Microsoft Quick Assist. Were you asked to grant permission after the initial install of Microsoft Quick Assist?
Microsoft Support is fond of telling customers over and over to use Microsoft Support. It's a thing they do. That doesn't sound alarming to me.
I would move Microsoft Quick Assist application to the trash and then empty the trash.