I’m not sure what you mean here. The panels appeared, but are not functioning?
If you open MATE Terminal from the console:
env DISPLAY=:0 mate-terminal
Then switch back with CTRL+ALT+F7… use the terminal to try loading the panels:
This might print out any errors to give a clue why the panels are not loading.
I would guess it’s most likely due to a configuration error in your home folder. If you don’t mind losing some configuration (e.g. bookmarks, web browser stuff, preferences for programs), I’d suggest creating a new user account and transferring your personal files.
From a terminal, this is the command for the Users & Groups window:
To log out:
If a new user (or guest session) does not work, then this is definitely a system-wide problem. It may be possible to re-install the panels if this is the case:
sudo apt install --reinstall mate-panel