Account Administrator left company unexpectedly

Our account administrator is suddenly no longer with the company. No forwarding information. His network account had to be disabled, so I can't even log in via SSO if I knew his password.

I urgently need to change myself to the account owner but cannot log in as him to make that happen.

I can't get ahold of anyone at support...I keep getting the message that my personal meeting ID doesn't exist, thought I use it constantly.

Anyone out there have any ideas???