Dear Sir,
I very much regret that I could not inform you that I could not reach the place of my appointment on the specified day. But I am hereby state that I was confined to bed and could not as a consequence do hardly anything. I, however, informed you as per my letter dated the __________________________, which, I hope, must have reached you.
I did not alter any programme and the information reaching you appears to be wrong. You may ascertain from ____________________________of _______________________whether I approached him on the specified date. I am assured you that I am faithfully discharging my duties ever since I got the appointment. Please excuse me for the trouble.
Yours faithfully,