Just had an email exchange with EH. Here is what they said:
So if you want to pay for shipping / repair you can go that way or a 3rd party PSU like the OneSpot or PowerAll should fix it.
I think i solved this today. Try using another power supply like a One-Spot, or PowerAll. I was using the EH wallwart that was included with the pedal which gave me the buzzing noise. Then i switched to the PowerAll and it is dead silent now.
I am also having this exact issue. Did you ever get it resolved? My click volume knob either seems to be totally off or on, no level adjustment. Anyone else have this problem?