My receipt is in the car which is now *back* at Mazda due to the axle falling out of the tranny. Good times.
The $800 labor they want is to basically tear the tranny apart, diagnose the problem and if it IS "abuse", then that'll cover the new clutch. If they are all ready saying it the clutch, I'd take your car to another place and get an ACT Z66-HDSS clutch installed. It'll be cheaper labor-wise and a lot better of a clutch. You can get 'em for around $350ish and labor is normally around $300, so you're just at 600 instead of 1300.
If the car still does not run after the clutch install, then take it to Mazda as it'll be a tranny problem and that has a high chance of being covered.
Bueno?