"Chaotic treatment plan"

I have been a patient at the Dental hospital for in excess of 4 years (Original estimate circa 18 months - restorative dentistry). For my latest appointment, I arrived at 0945 for a 1000 appointment, at 1005 I received a call to tell me that my appointment had been cancelled - The clinician had not turned up. My last 3 appointments (for fitment of 2 crowns) have all been a disaster. On each of the 3 occasions the crowns have been manufactured incorrectly (they did not fit!) As they are front teeth, the fit is rather critical! The first 2 years of my treatment seemed to be very professional and the staff (especially the nurses) could not have been better. However, the last 2 years the system appears to gone into "meltdown". To make the same mistake on 3 separate occasions seems incomprehensible - what makes it worse there seems to just a shrug of the shoulders and "We'll try to fit you in, in a couple of month’s time to try again". I do not know what the cost might be to keep making impressions of my teeth and then to make the crowns, but to keep making the same mistake repeatedly is getting beyond belief. I am writing to the hospital to ask for some sort of investigation to try to get the situation resolved - However, my expectation is quite low. What a great shame, I understand that the hospital is also a teaching hospital but where there appears to little or no supervision, mistakes will surely keep on happening.