I was able to fix without a re-install
go to Computer\HKEY_CURRENT_USER\SOFTWARE\IM Providers in regedit
Make sure the key "DefaultIMApp" is set to your preferred program, mine is "Teams"
Right click the key, disable inheritance and set it to read only.
I also deleted the Jabber key under IM Providers, but don't think this did anything in the end, worth trying though if above does not work
or set UpAndRunning to 0
extremely disappointing that cisco would force this on without a setting for it. Just scummy behaviour.