"Diabetes doctor"

I have type 2 diabetes. I am on insulin. This is monitored by the diabetes doctor. I am supposed to see the doctor twice a year but recently this has been once a year as my appointment keeps getting cancelled by the doctor. The last time I saw them I asked why and they said there were more cases worse than mine they had to see. The doctor seemed pleased with my progress. However I have received a letter from the doctor on Saturday 4 July 2015 and to be honest the tone is disgusting. The doctor says in the letter I have poor control and should have had a blood test. I had a blood test at the time of the appointment but it seems that someone hasn't passed the results on. The entire tone of the letter is arrogant and insulting and I am being treat like a 16 year old who hasn't been doing what he should. I have tried to do what I have been told but, without regular appointments, have been left to just get on with it especially as sometimes my blood sugar it too low and I should be taking insulin. I only hope this doctors bedside manner is better than their letter writing.