If that's labor alone "Ben-Dover!" Go get your bike. Before they disassemble it! Call them and tell them you are cancelling the work order. Fax them a notice of cancellation, requesting a written confirmation and a phone call to your cell, then go get your bike.
You could have one of the vendors on here work on it and with shipping and a lot of new parts, it might come to that. It depends on what needs to be replaced. Four slide/diaphragm assemblies is $400. You probably don't need four, but you might need none, one, or two. $is unfortunately 'to be determined' once the tear-down happens, and you see what's needed. In a 'worst-case' scenario, you could have damaged and unrepairable carb bodies, for instance, and then you would be better-off buying a known good-working set from one of the fueling specialists on here, like dannymax, Kyle or Sean Morley, who have spare sets either usable, or gone through, at a higher cost.
If I were you, send them to someone on here to fix for you, and you probably will undercut your dealer's price considerably.
I have a spare set of carbs, so I can swap mine out if I encounter an issue, and want to keep riding. I have a new fuel tank, so I don't have to worry about the same thing happening to my replacement carbs (slsoughing-off rust from a corroded tank clogging the replacements). The shop sould be replacing your fuel filter and at-least eyeballing your fuel delivery system while doing this work.
