I have contacted them and get responses after hours of waiting. I have called them three times over the past year and gotten decent customer service - they admit there are rare cases where the device can ruin a battery and not be discovered- that's what happened to me. i ruined 2 batteries in my lexus before the mechanic realized the hum was sucking all the life out of them. Usually there is some charge on batteries but these were completely dead.
Anyway, Hum promises me someone will return my calls and give me more information and I have gotten nothing from them. I sent them receipts and proof and they ignored me. I called and found out the case rep was fired and he neglected to pass me on to another rep. I had to call back a 3rd time because still no response and they had shoddy notes in their system, I had to start completely over AGAIN and still they promised me someone higher up would contact me but no one has....
If this is not resolved, I am taking it up with my credit card company first and then a lawyer.
My first sentence is a bit odd - I meant to say that it takes forever to get to the right person but if I have a few hours, I can finally work my way to someone at Hum customer service dept who at least says they will help me.