At the Superchargers that I have been to, there is an 877 number on the pedestals; 877-798-3752 takes you to a corporate voice menu that you can drill down to Supercharger support with a human answering. When I find a pedestal not working, charging slowly, etc, I give this number a call. The people on the other end are always courteous and thank me for giving them the reports, often verifying the status on the spot.
For those not wanting to wait the voicemail shortcut is 1, 2.