One of the worst experiences I've had with a Chevr...

One of the worst experiences I've had with a Chevrolet dealership. I dropped my car off for an 8am appointment to get a diagnostic for my Check Engine Light. Thinking this would only take 3 to 4 hours like always when I take my car to the dealership, I was fine with that. Remind you THIS WAS AN APPOINTMENT. I called twice to get an update on when my car would be finished. At 4pm I was told my car was being worked on. Now in addition to the $150 I was being charged just to do the diagnostic test, at 5:30pm I was told I needed a purge valve for my car and it would cost me an additional $150 for them to put that on. At that point I was furious because my car had been there 9 1/2 hours and I had to pay $300 to basically put a part on that was $33. Then I received a call at 6:52pm saying my car was ready for pick up (11 hours later) so I'm guessing my car was the last to be worked on. I got there about 7:15 and little did I know they closed at 7pm but online its says they close at 9pm. Again, this was one the worst experiences with a dealership and I will never bring my car back here for service.