"Look, I hate to say this, but I'm trimming a business, and I can't afford to spend an unlimited number of hours doing free customer support. A certain amount of that was budgeted into the contract, but we've already gone past that. I'd be glad to continue answering these small questions for you, but it will have to be at my usual hourly rate, or well need to work out some kind of contract for that service. Of course if you find a genuine bug covered by warranty, that's a different matter... but be prepared to pay it out turns out to user error/education/configuration work. I like you guys, but I need to work on my other customers' projects, and I need to eat."
Heck, even rms, one of the founders of the open source movement, said quite clearly that even when software is free, support should be paid for.
