Wow, that guy REALLY doesn't want to work on your car! I've seen that happen before AFTER someone's replaced an Evap SO I'd guess that that's what's happened to your car? If so, the upper part of the dash is held to the firewall by 4 long bolts that go into clips that attach to your dash. Sometimes when the dash is removed, those clips break or become stripped. Any dealer should stock those clips and they're not THAT hard to replace by a person with experience. One doesn't need to touch your heater unit housing the Evap and heater core, just loosen the dash enough to replace the broken clips. NOW....worst case senerio, the plastic tabs that hold the clips might be broken off (extreme butchery....seen that too) and if so, the choices are to either remove the dash and get creative or replace the dash (very costly).
Either way, it might take an experienced tech a couple hours at best to fix that BUT by no means will that cost you $1500.
You could do it yourself too if so inclined. If it's just the clips, you don't need to completely remove the dash but loosen it enough to gain access to the clips, possible if you know what you're looking for as I've done it.