Some stealerships try pull this crap. Wouldn't expect it from the stealership where you purchesed from though, that is piss poor. Many other car manufacturers, ie Lexus don't do this.
$300 a week and they are paying for the damn car. Then again, if they didn't charge you for it, they sure make up for it with their exorbatant prices. Tell them to jam it up their a## and book the car elsewhere.
It's probably only an oil service which they'll charge you $400 for when you can get it for 180-190 elsewhere.
I personally take mine to an independant and provided you have the paperwork, the warranty stays intact
