"Not happy"

Had an appointment on the 17th of October and was told it was cancelled the day before I was supposed to attend, with no explanation what so ever, I now have to wait until January but they can’t tell me why, I’ve tried ringing and left messages but no reply, I understand they are busy but telling me this the day before my appointment is a total let down! And now I have to tell my work that I am now able to work and that I’m sorry for messing my work schedule around.