Hello from Mendoza!

I arrived here yesterday via an overnight bus from BA. Not wanting to think, we decided to take the half day winery tour offered by many travel agents. This particular one, brought us to "Cavas de Don Arturo" & another. During the tasting, we tasted Cab '04 and it seems pretty good. So we decided to buy their Cab 04 & 03. Back at the hotel, we tried those wine and they seem different than the one we tasted.
During the tour, they said that they don't sell their wine anywhere else but US (some exclusive deal with some US company) so you won't see it in Argentina. I've googled the web but only came up with blogs from people that went to the same wine tour.
When we did the tasting, they didn't open the bottle in front of us, they already had it in a decanter. Now I'm wondering if that was some different wine they try to "bait & switch" on us. And this is their only means to sell the wine. It's a small winery, family run.
Have anyone heard of this winery?? or am I just being paranoid?