Dell's consumer support is the problem. Social Media is only the magnifying glass.
I think the question about how to use Social Media for consumer support is wrongheaded. The fallout Dell has faced in social media over the years is not due to poor social media management, but poor overall support of Dell's customer base. I was a long-time Dell customer until my last purchase. You puppies lost me for good. And I certainly used social media to explain all the reasons to the world.
Fix your support and social media will work to your advantage. Not the other way around.