Other: Dentist Pain, No Drill Involved!

I made a long-overdue dentist appointment last week for yesterday afternoon. As they didn't have anything early in the morning or late in the day until January, I had to make it for mid-afternoon and leave work early. When I got to the dentist office yesterday:

Receptionist: Oh, we called you 45 minutes ago. [After I'd already left for the appointment.] The dentist you made the appointment with no longer accepts your insurance. But you can make another appointment with a dentist in this office who does!
Me: Um, I left work early and came all this way. No one can see me now?
Receptionist: No. [Gets out appointment book.] When would you like to come in?
Me: Um, why don't I get back to you on that.

Like I'm going to patronize an office with staff so incompetent they've already wasted my time once? I gave them the insurance info last week and they waited until 45 minutes before the appointment to figure out that they didn't know which dentist took which insurance plan?