Hey gal!
I too am sorry about your watch, but not nearly surprised.
Cartier creates amazing watches, has customer service that is unreal. Babyclouds is right - Cartier sends almost everything back to Paris for repair. Normally the shop, whether it's Tourneau or any other jeweler, will never touch Cartier issues preferring instead to keep it completely "in house" with the manufacturer. I love the campany, but my SO waited 6 months for a replacement clasp, and I have waited an entire year for a standard strap for another watch! When I asked why, I was told they handmake everything and keep a very personal touch to everything, so customer service is very slow.
It really isn't Tourneau, although it is unfortunate to hear they treated you icily and were not as forthcoming as they might have been about everything. My advice is, however, you may wait a lot longer for that repair. Plan on it now, and console yourself (ha! as if! not much consolation I know) with the fact that it is being repaired by experts in Paris.
Sorry to say it, but Cartier is gorgeous... and kind of like an exercise in patience.