Here is contact info for their entire staff
I get my Camaro serviced at Classic, as well, since I work next door and my CPO has free maintenance for a while...I use a guy named Tim Foote and he's always been pretty cool; Granted, I literally just drive next-door, toss him my keys, and get someone to drive me the .5 miles down the 'road' to their body-shop so I can walk over to work...
...When I had Bette up on a lift to put on my Hawk-pads on, though, I did notice a little drip of oil at the bottom of the oil filter, and you could see all down the undercarriage where it had been dripping while driving and gotten blown back/up and on to shit...Weird thing is that I literally don't have ANY oil ANYWHERE that I park...I would have noticed, and I have checked...lol... =\
Classic is, like, the #1 Selling Chevy Store in the entire country, though...All you [probably] need to do is get in touch with your salesperson...since you said she was 'cool'...and she can [hopefully] help you get the direct ling for their Owner/General Manager, tell them everything you've said here, then tell him you wanted to give him a chance to make things right on his own before you contact GM Corporate...
If he doesn't respond AND figure out a way to make you happy, then I would call GM Consumer Affairs @ (800) 222-1020
Just don't come at him crazy...My GM/Owner will almost always take care of [a] customer(s) in your situation...unless they come at him sideways, in which case he will very politely tell them to **** off, while making them feel dumb AF, and we'll (Management and the vets) all laugh our asses off about it for weeks.