I'd do two things.
1) Make the phone number for support a premium number! Not ten bucks a minute premium, but offer them the premium number where you will help them or the non-premium number of the manufacturer.
2) Emails should 90% be fixed with a series of FAQs sitting in on your hard drive (actually, I use notes in my Yahoo account). I find that having these replies already templated makes email support MUCH MUCH easier. As you start to hate those support emails, it becomes harder and harder to reply to the same inane, "READ THE DARN MANUAL IDIOT" type question without sounding terse or rude. Templating the common replies gets you out of that dangerous stste of mind and also makes email support MUCH quicker.