Help! Can't download new version of app now Zoom has changed!

Hi, I've come back to work after a break to discover the new Zoom Workplace and am struggling to log into even my own meetings and now cant share screen (the presentations open on laptop are not showing as open in the share screen)

I've tried to download new version of app but it keeps saying i am on 5.5.10 and need version 5.16.6 or higher and to call my IT dept, I'm self employed and don't have an IT dept! I need to get this resolved quickly but can't even access the tech support by phone as i can't type in a £ sign it requests me to at end of id code!!