What?
I'm not trying to argue false dichotomies, but how then would you define good customer service? I think your informed and well-reasoned opinion will be quite telling in this respect.
I think some people have this idea that the customer is ALWAYS right and that if a retailer doesn't roll over and say yes to every demand, that they are not getting good customer service.
I've had people demand something be taken back by a retailer well after the return date fill out comment cards and slam CS representatives, at a retailer that took such things very seriously, just because they were given the right answer, which was "no".
I'd place the idea that Wizards declining to sell something anymore, for reasons they feel make sense in the current business climate for them in this category.
So- not selling 3rd edition, not selling Dragon and Dungeon as physical magazines, and not selling PDFs are most definitely not bad customer service.
They're just Wizards doing what they think is best for their business right now and discontinuing a product line.
You have every right to be unhappy about it. You have every right to feel its a dumb decision on their part.
But Wizards telling you something you don't want to hear is not bad CR.
As for what IS good customer service, its doing everything you reasonably can to make the customer experience a good one, being friendly, keeping the store clean, making the shopping experience an "all ages" environment for any kind of mainstream retail, having a professional staff etc.